2020-2021 Flu Season Summary

Updated October 25, 2021

2020-21 Flu Season Summary FAQ

Summary

What was the 2020-2021 flu season like?

Flu activity was unusually low throughout the 2020-2021 flu season both in the United States and globally, despite high levels of testing. During September 28, 2020–May 22, 2021 in the United States, 1,675 (0.2%) of 818,939 respiratory specimens tested by U.S. clinical laboratories were positive for an influenza virus. The low level of flu activity during this past season contributed to dramatically fewer flu illnesses, hospitalizations, and deaths compared with previous flu seasons. For comparison, during the last three seasons before the pandemic, the proportion of respiratory specimens testing positive for influenza peaked between 26.2% and 30.3%. In terms of hospitalizations, the cumulative rate of laboratory-confirmed influenza-associated hospitalizations in the 2020-2021 season was the lowest recorded since this type of data collection began in 2005. For pediatric deaths, CDC received one report of a pediatric flu death in a child during the 2020–2021 flu season. Since flu deaths in children became nationally notifiable in 2004, reported flu deaths in children had previously ranged from a low of 37 (during 2011-2012) to a high of 199 (during 2019-2020).

What are possible explanations for the unusually low flu activity?

COVID-19 mitigation measures such as wearing face masks, staying home, hand washing, school closures, reduced travel, increased ventilation of indoor spaces, and physical distancing, likely contributed to the decline in 2020-2021 flu incidence, hospitalizations and deaths. Influenza vaccination may also contributed to reduced flu illness during the 2020–2021 season. Flu vaccine effectiveness estimates for 2020-2021 are not available, but a record number of influenza vaccine doses (193.8 million doses) were distributed in the U.S. during 2020-2021.

How many people got vaccinated against flu during the 2020-2021 flu season and how does that compare to previous seasons?

CDC works each year to increase the number of people who receive a flu vaccine and eliminate barriers to vaccination. Influenza vaccine production and distribution in the US are primarily private sector endeavors, but during the 2020-2021 flu season, as part of efforts to maximize flu vaccination by increasing availability of vaccine, CDC purchased an additional 2 million doses of pediatric and 9.3 million doses of adult influenza vaccine to create a stockpile of vaccine in case of supply problems. While final estimates are pending, early estimates based on survey data suggest flu vaccination uptake for 2020-2021 was similar to the prior season, with small increases among some groups of people and small decreases among other groups of people. Preliminary estimates indicate that 50% to 55% of adults got a flu vaccine (compared with the 2019–2020 estimate of 48% by end of May 2020). Influenza vaccination coverage in children dropped 4.1 percentage points from 62.3% during 2019-2020 to 58.2% during 2020–2021 and estimates for pregnant people and health care personnel indicated slight decreases in influenza vaccine coverage. Racial and ethnic disparities in flu vaccine uptake persisted for children and adults. Because racial and ethnic minority groups might be at higher risk for developing serious illness, resulting from flu that may lead to hospitalization, flu vaccination is especially important for these communities.

Flu Activity

Did new flu viruses circulate during the 2020-2021 flu season?

Flu viruses are constantly changing so it’s not unusual for new flu viruses to appear each year. During the 2020-2021 flu season, there was very low circulation of seasonal flu viruses. During September 27, 2020–May 22, 2021 in the United States, 1,899 (0.2%) of 1,081,671 clinical samples tested were positive for an influenza virus (713 [37.5%] influenza A and 1,186 [62.5%] influenza B). During that same period, public health laboratories reported 61.4% of influenza positive samples were influenza A and 38.6% of positive samples were influenza B. The majority (52.5%) of influenza A viruses were H3N2, and the majority (60%) of influenza B viruses were of Victoria lineage.

In terms of novel influenza viruses, CDC reported five human infections with an influenza virus that usually spreads in pigs and not people (called a variant influenza virus) in the United States. All five of these infections occurred in people who reported that they had direct exposure to pigs or lived on a property where pigs were present. No person-to-person spread of variant influenza was identified associated with any of these patients. These types of infections occur in people rarely, and usually in the context of exposure to pigs, but are concerning because of their pandemic potential. Since 2005, a total of 489 variant influenza virus infections have been identified in the United States and reported to CDC.

More information about how flu viruses change is available.

Flu Vaccine

What flu viruses did the 2020-2021 flu vaccines protect against?

For 2020-2021, trivalent (three-component) egg-based vaccines contained:

  • A/Guangdong-Maonan/SWL1536/2019 (H1N1)pdm09-like virus (updated)
  • A/Hong Kong/2671/2019 (H3N2)-like virus (updated)
  • B/Washington/02/2019 (B/Victoria lineage)-like virus (updated)

Quadrivalent (four-component) egg-based vaccines, which protect against a second lineage of B viruses, contained:

  • The three recommended viruses above, plus B/Phuket/3073/2013-like (Yamagata lineage) virus.

For 2020-2021, cell- or recombinant-based vaccines contained:

  • A/Hawaii/70/2019 (H1N1)pdm09-like virus (updated)
  • A/Hong Kong/45/2019 (H3N2)-like virus (updated)
  • B/Washington/02/2019 (B/Victoria lineage)-like virus (updated)
  • B/Phuket/3073/2013-like (Yamagata lineage) virus

Were there any changes to the 2020-2021 Northern Hemisphere vaccines from what was included in 2019-2020 U.S. flu vaccines?

Yes, 2020-2021 flu vaccines were updated to better match the flu viruses that were expected to circulate in the United States.

  • The egg-based H1N1 vaccine component was updated from an A/Brisbane/02/2018 (H1N1)pdm09-like virus to an A/Guangdong-Maonan/SWL1536/2019 (H1N1)pdm09-like virus.
  • The cell- or recombinant-based H1N1 vaccine component was updated from an A/Brisbane/02/2018 (H1N1)pdm09-like virus to an A/Hawaii/70/2019 (H1N1)pdm09-like virus.
  • The egg-based H3N2 vaccine component was updated from an A/Kansas/14/2017 (H3N2)-like virus to an A/Hong Kong/2671/2019 (H3N2)-like virus.
  • The cell- or recombinant-based H3N2 vaccine component was updated from an A/Kansas/14/2017 (H3N2)-like virus to an A/Hong Kong/45/2019 (H3N2)-like virus.
  • The B/Victoria lineage vaccine component was updated from a B/Colorado/06/2017 (B/Victoria lineage)-like virus to a B/Washington/02/2019 (B/Victoria lineage)-like virus.
  • The B/Yamagata lineage vaccine component was not updated.

Were there any new vaccines licensed for use during the 2020-2021 flu season?

There were two new vaccines licensed for use during the 2020-2021 flu season.

  • The first was a quadrivalent high-dose vaccine licensed for use in adults 65 years and older. This vaccine replaced the previously licensed trivalent high-dose vaccine.
  • The second new vaccine for the 2020-2021 flu season was a quadrivalent adjuvanted vaccine licensed for use in adults 65 years and older.
  • This vaccine was similar to the previously licensed trivalent vaccine containing MF59 adjuvant, but it has one additional influenza B component.

More information about new vaccines available in 2020-2021.

What flu vaccines were recommended during the 2020-2021 season?

For the 2020-2021 flu season, providers could choose to administer any licensed, age-appropriate flu vaccine (IIV, RIV4, or LAIV4) with no preference for any one vaccine over another.

Vaccine options included:

Flu Vaccine Availability

How many flu vaccines were available for the 2020-2021 flu season?

Flu vaccine is produced by private manufacturers, so supply depends on manufacturers. For the 2020-2021 season, manufacturers projected they would provide as many as 194-198 million doses of flu vaccine, which is more than the 175 million dose record set during the 2019-2020 flu season. 193.8 million doses of flu vaccine had been distributed in the United States as of February 26, 2021—the highest number of doses in a single flu season. CDC provided weekly updates on total flu vaccine doses distributed throughout the 2020-2021 flu season.

Were there delays in the availability of flu vaccine?

Influenza vaccine manufacturers did not report any significant delays in national flu vaccine supply or distribution during 2020-2021.

Were there enough doses of flu vaccine available for the 2020-2021 flu season?

Yes. Vaccine manufactures reported distributing 193.8 million doses of flu vaccine in the United States as of February 26, 2021. This was more flu vaccine than had ever previously been distributed in the United States. Some of this distributed vaccine was likely was not administered. In the United States in general, every year, there are a number of doses of flu vaccine that go unused. CDC provided weekly updates on total flu vaccine doses distributed throughout the 2020-2021 flu season.

Flu Vaccines During the COVID-19 Pandemic

Did we need to get a flu vaccine earlier during the 2020-2021 flu season (i.e. July/August)?

There was no change in CDC’s recommendation on timing of vaccination last flu season. Getting vaccinated in July or August is too early, especially for older people, because of the likelihood of reduced protection against flu later in the flu season. September and October are good times to get vaccinated. However, as long as flu viruses are circulating, vaccination should continue, even in January or later.

More information for vaccination timing for the 2020-2021 flu season

Were there changes in how and where flu vaccines were given in fall and winter or 2020-2021?

Prior to the 2020-2021 flu season, CDC worked with health care providers and state and local health departments to develop contingency plans on how to vaccinate people against flu without increasing their risk of exposure to respiratory disease, like the virus that causes COVID-19. This included releasing  Interim Guidance for Immunization Services During the COVID-19 Pandemic. Preliminary coverage data from September 2020 suggest there were some changes in where people got vaccinated early in 2020-2021. For example, the proportion of people reporting getting a flu vaccination at a store (53.8%) was significantly higher than the equivalent proportion for the 2019–20 season (34.9%), and the proportion reporting vaccination at a doctor’s office was significantly lower than 2019–20 (29.7% vs 37.3%).

Were flu vaccines and COVID-19 vaccines given at the same time during the 2020-2021 season?

No. As recommended by ACIP  during the 2020-2021 flu season, out of an abundance of caution, COVID-19 vaccines were administered alone, with a minimum interval of 14 days before or after administration of any other vaccines, including influenza vaccines.

This recommendation has since been updated.

What did CDC do to promote flu vaccination during the COVID-19 pandemic?

To address the importance of flu vaccination, especially during the COVID-19 pandemic, CDC increased the availability of vaccine, including purchasing an additional 2 million doses of pediatric flu vaccine and 9.3 million doses of adult flu vaccine to create a stockpile of vaccine in case of supply problems. CDC also emphasized the importance of flu vaccination for the entire flu season and conducted targeted communication outreach to specific groups who are at higher risk for complications from flu. These same groups are often at higher risk for COVID-19, too, so protecting them from influenza was important to decrease their risk of co-infection. Communication strategies for providers and the public included:

  • Educational outreach activities by CDC, including social media, press conferences, web page spotlights, radio media tours, op-eds, and other publications,
  • A digital campaign to educate the general public and people with who are at increased risk from influenza and COVID-19 complications,
  • Special educational efforts to inform the general population, people with underlying health conditions, and African American and Hispanic audiences about the importance of flu vaccination, and
  • Updated vaccination websites for the public and providers that highlight the safety precautions being implemented in health care facilities during the pandemic.

Flu Vaccine Coverage

What vaccine uptake estimates did CDC provide during the 2020-2021 season?

CDC developed a new Weekly National Influenza Vaccination Dashboard designed to share preliminary, in-season, weekly influenza vaccination coverage estimates and related data.

The dashboard included information on the number of influenza vaccine doses distributed in the United States, weekly flu vaccination coverage rates for children 6 months – 17 years old, monthly flu vaccination coverage rates among pregnant persons, and information on how many flu vaccines were administered in pharmacies and doctor’s offices.

The data was updated weekly or monthly, depending on the data source, throughout the 2020-2021 influenza season; other data sources were added as they become available. Visit the National Influenza Vaccination Dashboard for more information.

CDC also provided seasonal flu vaccination coverage estimates at the end of flu season.

How did CDC track weekly flu vaccination coverage among children 6 months – 17 years old?

Influenza vaccination coverage among children was assessed through the National Immunization Survey-Flu (NIS-Flu), which provided weekly influenza vaccination coverage estimates for children 6 months–17 years old. NIS-Flu is a national random-digit-dialed cellular telephone survey of households conducted during the flu season (October-June). Additional information about NIS-Flu methods and estimates from 2019-2020 season are available at FluVaxView.

How did CDC track monthly flu vaccination coverage among pregnant women?

Monthly flu vaccination coverage estimates among pregnant women are based on electronic health record (EHR) data from the Vaccine Safety Datalink (VSD), a collaboration between CDC’s Immunization Safety Office and nine integrated health care organizations. Of note, because these estimates are based on data from nine integrated health care systems, they may not be representative of all pregnant women in the U.S.

How did CDC track the number of flu vaccines administered at pharmacies and doctor’s offices?

CDC tracked the number of flu vaccines administered at pharmacies and doctor’s offices by using new sources of vaccination data, including IQVIAexternal icon data for vaccinations administered in retail pharmacies (e.g., chain, mass merchandise, food stores, and independent pharmacies) and doctor’s offices.

When were the first flu vaccine uptake estimates provided the 2020-2021 season?

CDC launched the first weekly FluVaxView dashboard in December. The number of flu vaccine doses distributed, vaccination coverage estimates for children, and vaccinations administered in retail pharmacies and doctor’s offices were updated weekly. Coverage estimates for pregnant women were updated monthly. Visit the National Influenza Vaccination Dashboard for more information.

Was this the same kind of vaccine uptake information that has been provided in the past?

For each flu season since 2009-2010, CDC has estimated annual influenza vaccination coverage for the United States by using data from several nationally representative surveys: the Behavioral Risk Factor Surveillance System (BRFSS), the National Health Interview Survey (NHIS), and the National Immunization Survey-Flu (NIS-Flu). Internet panel surveys of adultshealth care personnel, and pregnant women are also used.

Click here for vaccination coverage estimates from past flu seasons. CDC will continue to provide end of season estimates of influenza vaccination coverage from these data sources.

For the 2020-21 flu season, CDC provided weekly updates on the number of flu vaccine doses distributed, vaccination coverage estimates for children, and the number of doses administered in pharmacies and doctor’s offices. Coverage estimates for pregnant women were updated monthly.

Is CDC working to improve influenza vaccine uptake data?

CDC is exploring non-survey data sources, such as claims and other administrative data, to track flu vaccination coverage.  For example, CDC is exploring ways to estimate within-season influenza vaccination coverage among adults using data on the number of doses administered in pharmacies and doctor’s offices and estimates of the proportion of all influenza vaccinations that are received in these settings.  CDC supports state and local jurisdictions in use of their immunization information systems to assess influenza vaccination coverage at the jurisdictional level.

Flu Surveillance Data Updates

Were there any updates in the methods for flu surveillance for 2020-2021?

For the 2020-2021 flu season, there were some changes to FluView surveillance methodology.

In addition to state-level data, the influenza-like-illness (ILI) activity map displayed ILI activity by Core-based Statistical Areas (CBSA), a U.S. geographic area defined by the Office of Management and Budget (OMB) that consists of one or more counties (or equivalents) anchored by an urban center of at least 10,000 people plus adjacent counties that are socioeconomically tied to the urban center by commuting.

Also, during most flu seasons, state and territorial health departments report the level of geographic spread of flu activity in their jurisdictions each week through the State and Territorial Epidemiologists Report. However, because COVID-19 and influenza have similar symptoms and it is difficult to differentiate the two without laboratory testing, reporting for this system was suspended for the 2020-21 influenza season.

Finally, NCHS collects death certificate data for all deaths occurring in the United States, and these data are aggregated by the week of death occurrence. In previous flu seasons, the NCHS surveillance data were used to calculate the percent of all deaths occurring each week that had pneumonia and/or influenza (P&I) listed as a cause of death. Because many COVID-19-related deaths also have pneumonia, COVID-19 coded deaths were added to P&I to create the PIC (pneumonia, influenza, and/or COVID-19) classification. PIC includes all deaths with pneumonia, influenza, and/or COVID-19 listed on the death certificate.

More information on flu surveillance methodology and these updates is available online.

Why was pneumonia, influenza, and COVID-19 (PIC) mortality data added to FluView Interactive?

CDC monitors flu deaths each week using death certificate data collected by the National Center for Health Statistics (NCHS). NCHS mortality surveillance data was used in previous years to calculate the percentage of all U.S. deaths occurring each week that had pneumonia and/or influenza (P&I) listed as a cause of death on the death certificate. Pneumonia is included because it is a frequent complication of severe influenza and increases in flu activity are associated with increases in pneumonia deaths. The weekly percentage of P&I deaths is compared to the expected percentage of deaths due to pneumonia to estimate the increase in pneumonia deaths, or excess deaths, due to influenza.  Because pneumonia is also a frequent cause of death among people with COVID-19, COVID-19 coded deaths were added to P&I to create the PIC (pneumonia, influenza and/or COVID-19) mortality classification. CDC has displayed PIC mortality in its FluView report since week 40 of 2020. In addition, to make these data more easily downloadable and interactive, CDC incorporated PIC mortality data into its FluView Interactive data dashboard, an online data resource that accompanies the FluView report. Using FluView Interactive, users can download flu data and view this data via detailed, interactive graphs, charts, maps, and other visualizations.

Archived 2020-2021 Flu Season FAQ, as of July 20, 2021

Flu Vaccine

There are many different flu viruses and they are constantly changing. The composition of U.S. flu vaccines is reviewed annually and updated as needed to match circulating flu viruses. Flu vaccines protect against the three or four viruses (depending on the vaccine) that research suggests will be most common.

For 2020-2021, trivalent (three-component) egg-based vaccines are recommended to contain:

  • A/Guangdong-Maonan/SWL1536/2019 (H1N1)pdm09-like virus (updated)
  • A/Hong Kong/2671/2019 (H3N2)-like virus (updated)
  • B/Washington/02/2019 (B/Victoria lineage)-like virus (updated)

Quadrivalent (four-component) egg-based vaccines, which protect against a second lineage of B viruses, are recommended to contain:

  • the three recommended viruses above, plus B/Phuket/3073/2013-like (Yamagata lineage) virus.

For 2020-2021, cell- or recombinant-based vaccines are recommended to contain:

  • A/Hawaii/70/2019 (H1N1)pdm09-like virus (updated)
  • A/Hong Kong/45/2019 (H3N2)-like virus (updated)
  • B/Washington/02/2019 (B/Victoria lineage)-like virus (updated)
  • B/Phuket/3073/2013-like (Yamagata lineage) virus

Yes, this season’s flu vaccines were updated to better match viruses expected to be circulating in the United States.

  • The egg-based H1N1 vaccine component was updated from an A/Brisbane/02/2018 (H1N1)pdm09-like virus to an A/Guangdong-Maonan/SWL1536/2019 (H1N1)pdm09-like virus.
  • The cell- or recombinant-based H1N1 vaccine component was updated from an A/Brisbane/02/2018 (H1N1)pdm09-like virus to an A/Hawaii/70/2019 (H1N1)pdm09-like virus.
  • The egg-based H3N2 vaccine component was updated from an A/Kansas/14/2017 (H3N2)-like virus to an A/Hong Kong/2671/2019 (H3N2)-like virus.
  • The cell- or recombinant-based H3N2 vaccine component was updated from an A/Kansas/14/2017 (H3N2)-like virus to an A/Hong Kong/45/2019 (H3N2)-like virus.
  • The B/Victoria lineage vaccine component was updated from a B/Colorado/06/2017 (B/Victoria lineage)-like virus to a B/Washington/02/2019 (B/Victoria lineage)-like virus.
  • The B/Yamagata lineage vaccine component was not updated.

Are there any new vaccines licensed for use during the 2020-2021 flu season?

There are two new vaccines licensed for use during the 2020-2021 flu season.

  • The first is a quadrivalent high-dose vaccine licensed for use in adults 65 years and older. This vaccine will replace the previously licensed trivalent high-dose vaccine.

The second new vaccine that will be available is a quadrivalent adjuvanted vaccine licensed for use in adults 65 years and older.

  • This vaccine is similar to the previously licensed trivalent vaccine containing MF59 adjuvant, but it has one additional influenza B component.

More information about new vaccines available this year.

For the 2020-2021 flu season, providers may choose to administer any licensed, age-appropriate flu vaccine (IIV, RIV4, or LAIV4) with no preference for any one vaccine over another.

Vaccine options this season include:

There is no change in CDC’s recommendation on timing of vaccination this flu season. Getting vaccinated in July or August is too early, especially for older people, because of the likelihood of reduced protection against flu infection later in the flu season. September and October are good times to get vaccinated. However, as long as flu viruses are circulating, vaccination should continue, even in January or later.

More information for vaccination timing this year.

How and where people get a flu vaccine may need to change due to the COVID-19 pandemic. CDC works with healthcare providers and state and local health departments to develop contingency plans on how to vaccinate people against flu without increasing their risk of exposure to respiratory germs, like the virus that causes COVID-19, and has released Interim Guidance for Immunization Services During the COVID-19 Pandemic. More information is available in the ‘Administering Flu Vaccines during the COVID-19 Pandemic’ section below.

Some settings that usually provide flu vaccine, like workplaces, may not offer vaccination this upcoming season, because of the challenges with maintaining social distancing. For more information on where you can get a flu vaccine, visit www.vaccinefinder.orgexternal iconexternal icon. Information on getting a flu vaccine safely this season is available in the ‘Getting a Flu Vaccine during the COVID-19 Pandemic’ section below.

Flu vaccine is produced by private manufacturers, so supply depends on manufacturers. For the 2020-2021 season, manufacturers have projected they will provide as many as 194-198 million doses of flu vaccine, which is more than the 175 million dose record set during the 2019-2020 flu season.

Currently, influenza vaccine manufacturers are not reporting any significant delays in national flu vaccine supply or distribution this season.

Influenza vaccine production and distribution in the US are primarily private sector endeavors. CDC encourages manufacturers and distributors to use a distribution strategy in which providers receive smaller shipments to allow as many providers as possible to begin vaccination activities early in the vaccination season. Ideally, the intervals between shipments are short so that each provider has a continuous supply and can continue vaccinating patients without interruption. While no significant delays have been reported, in some places, robust demand for vaccine and supplies required to support flu vaccination efforts, like needles or syringes, may mean that some providers run out of vaccine or other supplies before their next shipment has arrived. While an allocation system can initially limit the size of individual orders, as supplies become available in increasing numbers, supply is expected to catch up with demand. Additionally, because vaccine manufacturing has been extended to support the production of a record number of flu vaccine doses this year, providers are likely to receive more shipments throughout the season.

To make sure your provider has flu vaccine available, call ahead to confirm availability. There also may be other locations in your area that have vaccine available. Use the VaccineFinderexternal icon to find out where to get vaccinated near you.

CDC will continue to provide weekly updates on total flu vaccine doses distributed throughout the 2020-2021 flu season.

Vaccine manufactures have said that they will produce between 194 and 198 million doses of flu vaccine this season. While this isn’t enough for every person in the U.S. to receive a flu vaccine this season, not everyone chooses to get vaccinated. For example, last season, only about half of Americans chose to get a flu vaccine and, in general, there are many doses of flu vaccine that go unused every season.

That said, demand for flu vaccine may be greater this season because of the COVID-19 pandemic. And while it would be unusual, it is possible that all flu vaccines will be used this season. CDC’s goal is for every available dose of flu vaccine to be used to protect people from flu. To make sure your provider has flu vaccine available, call ahead. There also may be other locations in your area that have vaccine available. Use the VaccineFinderexternal icon to find out where to get vaccinated near you.

CDC will continue to provide weekly updates on total flu vaccine doses distributed throughout the 2020-2021 flu season.

CDC does not have a preferential recommendation for any flu vaccine over another, and vaccination should not be delayed to wait on a specific vaccine product when another vaccine licensed for use in adults is available.

There are several flu vaccine formulations that are approved for use in people 65 and older, including two so-called “enhanced” flu vaccines: the high dose flu vaccine and the adjuvanted flu vaccine. Both vaccines are specifically designed to create a stronger immune response in people aged 65 years and older.

Another recent studyexternal icon showed that a vaccine made using recombinant technology can also produce a stronger immune response in adults 65 years and older.

For those having trouble locating “enhanced” vaccines licensed for use in people 65 years and older, call providers ahead of time to check availability. There also may be other locations in your area that have vaccine available. Use VaccineFinderexternal icon to find out where to get vaccinated near you.

How to locate high-dose and adjuvanted flu vaccine using VaccineFinder:

  1. Visit VaccineFinder.orgexternal icon
  2. Click “Find Vaccines”
  3. Click “Select your vaccines”
  4. Select “Flu Shot (65+)” and then click “Add 1 Vaccine”
  5. Enter your address or zip code
  6. Click “Search For Vaccine”
  7. Choose a vaccine provider from the list that appears or choose an option from the map.
  8. Call ahead to confirm availability and then get your flu vaccine from your chosen provider.

CDC recommends use of any licensed, age-appropriate influenza vaccine during the 2020-2021 influenza season, including inactivated influenza vaccine, high-dose influenza vaccine, adjuvanted influenza vaccine, or recombinant flu vaccine.

Vaccination should not be delayed to wait on a specific vaccine product when another age-appropriate vaccine is available.

No widespread needle shortages or supply interruptions have been reported. Adequate supplies are expected to be available to support both the 2020–2021 influenza vaccination program and routine vaccination efforts. However, due to high demand for influenza vaccination in some locations, there may be some limited or temporarily unavailable supplies of specific types of needles and needle/syringe sets. CDC has developed a resource guide for providers who are experiencing problems with purchasing needles for influenza and routine vaccinations.

Flu and COVID-19

Influenza (Flu) and COVID-19 are both contagious respiratory illnesses, but they are caused by different viruses. COVID-19 is caused by infection with a new coronavirus (called SARS-CoV-2) and flu is caused by infection with influenza viruses. Because some of the symptoms of flu and COVID-19 are similar, it may be hard to tell the difference between them based on symptoms alone, and testing may be needed to help confirm a diagnosis.

COVID-19 seems to spread more easily than flu and causes more serious illnesses in some people. It can also take longer before people show symptoms and people can be contagious for longer.

While more is learned every day, there is still a lot that is unknown about COVID-19 and the virus that causes it. This page compares COVID-19 and flu, given the best available information to date.

To learn more about COVID-19, visit Coronavirus (COVID-19).

To learn more about flu, visit Influenza (Flu).

While it’s not possible to say with certainty what will happen in the fall and winter, CDC believes it’s likely that flu viruses and the virus that causes COVID-19 will both be spreading. In this context, getting a flu vaccine will be more important than ever. CDC recommends that all people 6 months and older get a yearly flu vaccine.

Yes. It is possible have flu, as well as other respiratory illnesses, and COVID-19 at the same time. Health experts are still studying how common this can be.

Some of the symptoms of flu and COVID-19 are similar, making it hard to tell the difference between them based on symptoms alone. Diagnostic testing can help determine if you are sick with flu or COVID-19.

Yes. CDC has developed a test that will check for A and B type seasonal flu viruses and SARS CoV-2, the virus that causes COVID-19. This test will be used by U.S. public health laboratories. Testing for these viruses at the same time will give public health officials important information about how flu and COVID-19 are spreading and what prevention steps should be taken. The test will also help public health laboratories save time and testing materials, and to possibly return test results faster.

The Food and Drug Administration (FDA) has given CDC an Emergency Use Authorizationexternal iconexternal icon for this new test. Initial test kits were sent to public health laboratories in early August 2020. CDC will continue to manufacture and distribute these kits.

More information for laboratories is available.

No. This new test is designed for use at CDC-supported public health laboratories at state and local levels, where it will supplement and streamline surveillance for flu and COVID-19. The use of this specialized test will be focused on public health surveillance efforts and will not replace any COVID-19 tests currently used in commercial laboratories, hospitals, clinics, and other healthcare settings.

CDC’s first viral test for SARS-CoV-2 (the CDC 2019-nCoV Real-Time RT-PCR Diagnostic Panel (ER-34)) will still be available for qualified laboratories to order through the International Reagent Resource (IRR)external iconexternal icon. The new multiplex assay can also be ordered through the IRR. Check the IRR website for details.

For additional questions, please visit: Clinical Questions about COVID-19: Questions and Answers: Testing, Diagnosis, and Notification

Flu and COVID-19 can both result in serious illness, including illness resulting in hospitalization or death. While there is still much to learn about COVID-19, recent studies show it does seem as if COVID-19 is more deadly than seasonal influenza.

Getting a flu vaccine will not protect against COVID-19, however flu vaccination has many other important benefits. Flu vaccines have been shown to reduce the risk of flu illness, hospitalization and death. Getting a flu vaccine this fall will be more important than ever, not only to reduce your risk from flu but also to help conserve potentially scarce health care resources.

There is no evidence that getting a flu vaccination increases your risk of getting sick from a coronavirus, like the one that causes COVID-19.

You may have heard about a studyexternal iconexternal icon published in January 2020 that reported an association between flu vaccination and risk of four commonly circulating seasonal coronaviruses, but not the one that causes COVID-19. This report was later found to be incorrect.

The results from that initial study led researchers in Canada to look at their data to see if they could find similar results in their population. The results from Canada’s studyexternal iconexternal icon showed that flu vaccination did not increase risk for these seasonal coronaviruses. The Canadian findings highlighted the protective benefits of flu vaccination.

The Canadian researchers also identified a flaw in the methods of the first study, noting that it violated the part of study design that compares vaccination rates among patients with and without flu (test negative design). This flaw led to the incorrect association between flu vaccination and seasonal coronavirus risk. When these researchers reexamined data from the first study using correct methods, they found that flu vaccination did not increase risk for infection with other respiratory viruses, including seasonal coronaviruses.

To address the importance of influenza vaccination, especially during the COVID-19 pandemic, CDC will maximize flu vaccination by increasing availability of vaccine, including purchasing an additional 2 million doses of pediatric flu vaccine and 9.3 million doses of adult flu vaccine, by emphasizing the importance of flu vaccination for the entire flu season, and by conducting targeted communication outreach to specific groups who are at higher risk for complications from flu. These same groups are often at higher risk for COVID-19 too, so protecting them from influenza is important to decrease their risk of co-infection. Communication strategies for providers and the public will include:

  • Educational outreach activities by CDC, including social media, press conferences, web page spotlights, radio media tours, op-eds, and other publications,
  • A digital campaign to educate the general public and people with who are at increased risk from influenza and COVID-19 complications,
  • Special educational efforts to inform the general population, people with underlying health conditions, and African American and Hispanic audiences about the importance of flu vaccination, and
  • Updated vaccination websites for the public and providers that highlight the safety precautions being implemented in healthcare facilities during the pandemic.

Because COVID-19 is still a relatively new illness, there is little data on how flu illness affects the risk of getting COVID-19. In general, getting sick with one virus, like flu, doesn’t affect being infected with another, like the virus that causes COVID-19.  We do know that people can be infected with flu viruses and the virus that causes COVID-19 at the same time. Getting a flu vaccine can reduce your risk of getting flu.

Although there are some differences between flu and COVID-19, they also share signs and symptoms. For this reason, it may be hard to tell the difference between them based on symptoms alone. Testing may be needed to help confirm a diagnosis. Get more information on symptoms of COVID-19 and flu.

Providers may have different procedures and practices for evaluating and treating flu during the COVID-19 pandemic. If you have flu symptoms and are at high risk of serious flu complications, you should call your health care provider as soon as possible to tell them about your symptoms. Your provider may decide to treat you with flu antiviral medications. Follow your health care provider’s and CDC’s recommendations for doctor visits. Continue to take everyday preventive actions.

Getting a Flu Vaccine during the COVID-19 Pandemic

Yes. Getting a flu vaccine is an essential part of protecting your health and your family’s health this season. To protect your health when getting a flu vaccine, follow CDC’s recommendations for running essential errands and doctor visits. Continue to take everyday preventive actions.

When going to get a flu vaccine, practice everyday preventive actions and follow CDC recommendations for running essential errands.

Ask your doctor, pharmacist, or health department if they are following CDC’s vaccination pandemic guidance. Any vaccination location following CDC’s guidance should be a safe place for you to get a flu vaccine.

You can safely get a flu vaccine at multiple locations including your doctor’s office, health departments, and pharmacies. You can use VaccineFinder.orgexternal iconexternal icon to find where flu vaccines are available near you. When going to get a flu vaccine, be sure to practice everyday preventive actions.

Ask your doctor, pharmacist, or health department if they are following CDC’s vaccination pandemic guidance. Any vaccination location following CDC’s guidance should be a safe place for you to get a flu vaccine.

Vaccination of people at high risk for flu complications is especially important to decrease their risk of severe flu illness. Many people at higher risk from flu also seem to be at higher risk from COVID-19. If you are at high risk, it is especially important for you to get a flu vaccine this year.

Wearing a mask and social distancing can help protect you and others from respiratory viruses, like flu and COVID-19, but best way to prevent flu illness is for everyone 6 months and older to be vaccinated each year.

No, you should not delay getting a flu vaccine. While flu activity may be low in your community now, it could begin increasing at any time. Remember, it takes about two weeks after vaccination to develop antibodies that provide protection against flu. Ideally, you should get vaccinated before flu viruses begin circulating in your community. Everyone 6 months and older should get a flu vaccine each year.

For people who are sick with COVID-19 and who are already in a medical setting (for example, are in a hospital or other health care setting), flu vaccination should be deferred until they are no longer acutely ill.

 For those who are sick with COVID-19 or think they might have COVID-19, it is important to stay home and stay away from other people, unless medical care is required. Those who are not in a medical care setting (for example, are isolating at home), should wait until they meet criteria for leaving isolation (even if they have no symptoms) to come to a vaccination setting in order to avoid spreading COVID-19 to others in the vaccination setting. CDC has guidance for when you can be around others after having COVID-19.

Yes. CDC has resources to help with vaccine planning during the COVID-19 pandemic. Ask your doctor, pharmacist, or health department if they are following CDC’s vaccination pandemic guidance.  And protect yourself by practicing everyday preventive actions.

If you don’t have a doctor that you regularly see, flu vaccines are also available at locations including health departments and pharmacies. You can use VaccineFinder.orgexternal iconexternal icon to find where flu vaccines are available near you.

Information on getting a COVID-19 vaccine at the same time as other vaccines is available.
(Redirect added July 20, 2021).

Flu Activity

Flu viruses are constantly changing so it’s not unusual for new flu viruses to appear each year. More information about how flu viruses change is available.

The timing of flu is difficult to predict and can vary in different parts of the country and from season to season.

For the 2020-2021 flu season, there are some changes to FluView surveillance methodology.

This season, in addition to state-level data, the influenza-like-illness (ILI) activity map will display ILI activity by Core-based Statistical Areas (CBSA), a U.S. geographic area defined by the Office of Management and Budget (OMB) that consists of one or more counties (or equivalents) anchored by an urban center of at least 10,000 people plus adjacent counties that are socioeconomically tied to the urban center by commuting.

Also, during most flu seasons, state and territorial health departments report the level of geographic spread of flu activity in their jurisdictions each week through the State and Territorial Epidemiologists Report. However, due to the impact of COVID-19 on ILI surveillance, and the facts that the state and territorial epidemiologists report relies heavily on ILI activity, reporting for this system will be suspended for the 2020-21 influenza season.

Finally, NCHS collects death certificate data for all deaths occurring in the United States, and these data are aggregated by the week of death occurrence. In previous flu seasons, the NCHS surveillance data were used to calculate the percent of all deaths occurring each week that had pneumonia and/or influenza (P&I) listed as a cause of death. Because of the ongoing COVID-19 pandemic, COVID-19 coded deaths were added to P&I to create the PIC (pneumonia, influenza, and/or COVID-19) classification. PIC includes all deaths with pneumonia, influenza, and/or COVID-19 listed on the death certificate.

More information on flu surveillance methodology and these updates is available online.

Flu Vaccine Coverage

CDC has developed a new Weekly National Influenza Vaccination Dashboard designed to share preliminary, in-season, weekly influenza vaccination coverage estimates and related data.

The dashboard will include information on the number of influenza vaccine doses distributed in the United States, weekly flu vaccination coverage rates for children 6 months – 17 years old, monthly flu vaccination coverage rates among pregnant persons, and information on how many flu vaccines have been administered in pharmacies and doctor’s offices.

The data will be updated weekly or monthly, depending on the data source, throughout the 2020-2021 influenza season; other data sources will be added as they become available. Visit the National Influenza Vaccination Dashboard for more information.

 

CDC also provides seasonal flu vaccination coverage estimates at the end of a flu season. However, those estimates are not usually available until several months after the flu season ends.

Influenza vaccination coverage among children is assessed through the National Immunization Survey-Flu (NIS-Flu), which provides weekly influenza vaccination coverage estimates for children 6 months–17 years old. NIS-Flu is a national random-digit-dialed cellular telephone survey of households conducted during the flu season (October-June). Additional information about NIS-Flu methods and estimates from 2019-2020 season are available at FluVaxView.

Monthly flu vaccination coverage estimates among pregnant women are based on electronic health record (EHR) data from the Vaccine Safety Datalink (VSD), a collaboration between CDC’s Immunization Safety Office and nine integrated health care organizations. Of note, because these estimates are based on data from nine integrated health care systems, they may not be representative of all pregnant women in the U.S.

CDC is tracking the number of flu vaccines administered at pharmacies and doctor’s offices by utilizing new sources of vaccination data, including IQVIAexternal icon data for vaccinations administered in retail pharmacies (e.g.,  chain, mass merchandise, food stores, and independent pharmacies) and doctor’s offices.

CDC will launch the first weekly FluVaxView dashboard in December. The number of flu vaccine doses distributed, vaccination coverage estimates for children, and vaccinations administered in retail pharmacies and doctor’s offices will be updated weekly. Coverage estimates for pregnant women will be updated monthly. Visit the National Influenza Vaccination Dashboard for more information.

Each flu season since 2009-2010, CDC has estimated annual influenza vaccination coverage for the United States by utilizing data from several nationally representative surveys: the Behavioral Risk Factor Surveillance System (BRFSS), the National Health Interview Survey (NHIS), and the National Immunization Survey-Flu (NIS-Flu). Internet panel surveys of adultshealth care personnel, and pregnant women are also used.

Click here for vaccination coverage estimates from past flu season. CDC will continue to provide end of season estimates of influenza vaccination coverage from these data sources.

 

For the 2020-21 flu season, CDC will provide weekly updates on the number of flu vaccine doses distributed, vaccination coverage estimates for children, and the number of doses administered in pharmacies and doctor’s offices. Coverage estimates for pregnant women and will be updated monthly.

CDC is exploring non-survey data sources, such as claims and other administrative data, to track flu vaccination coverage.  For example, CDC is exploring ways to estimate within-season influenza vaccination coverage among adults using data on the number of doses administered in pharmacies and doctor’s offices and estimates of the proportion of all influenza vaccinations that are received in these settings.  CDC supports state and local jurisdictions in use of their immunization information systems to assess influenza vaccination coverage at the jurisdictional level.

Administering Flu Vaccines During the COVID-19 Pandemic

CDC has released Interim Guidance for Immunization Services During the COVID-19 Pandemic. This guidance is intended to help immunization providers in a variety of clinical and alternative settings with the safe administration of vaccines during the COVID-19 pandemic. This guidance will be continually reassessed and updated based on the evolving epidemiology of COVID-19 in the United States. Healthcare providers who give vaccines should also consult guidance from state, local, tribal, and territorial health officials.

For the complete interim guidance for immunization services during the COVID-19 pandemic.

Efforts to reduce the spread of COVID-19, such as stay-at-home and shelter-in-place orders, have led to decreased use of routine preventive medical services, including immunization services. Ensuring that people continue or start getting routine vaccinations during the COVID-19 pandemic is essential for protecting people and communities from vaccine-preventable diseases and outbreaks, including flu. Routine vaccination prevents illnesses that lead to unnecessary medical visits and hospitalizations, which further strain the healthcare system.

For the upcoming flu season, flu vaccination will be very important to reduce flu because it can help reduce the overall impact of respiratory illnesses on the population and thus lessen the resulting burden on the healthcare system during the COVID-19 pandemic.

A flu vaccine may also provide several individual health benefits, including keeping you from getting sick with flu, reducing the severity of your illness if you do get flu and reducing your risk of a flu-associated hospitalization.

Annual flu vaccination is recommended for everyone 6 months of age and older, with rare exceptions, because it is an effective way to decrease flu illnesses, hospitalizations, and deaths.

During the COVID-19 pandemic, reducing the overall burden of respiratory illnesses is important to protect vulnerable populations at risk for severe illness, the healthcare system, and other critical infrastructure. Thus, healthcare providers should use every opportunity during the influenza vaccination season to administer influenza vaccines to all eligible persons, including;

  • Essential workers: Including healthcare personnel (including nursing home, long-term care facility, and pharmacy staff) and other critical infrastructure workforce
  • Persons at increased risk for severe illness from COVID-19: Including adults aged 65 years and older, residents in a nursing home or long-term care facility, and persons of all ages with certain underlying medical conditions. Severe illness from COVID-19 has been observed to disproportionately affect members of certain racial/ethnic minority groups
  • Persons at increased risk for serious influenza complications: Including infants and young children, children with neurologic conditions, pregnant women, adults aged 65 years and older, and other persons with certain underlying medical conditions

No. Vaccination should be deferred (postponed) for people with suspected or confirmed COVID-19, regardless of whether they have symptoms, until they have met the criteria to discontinue their isolation. While mild illness is not a contraindication to flu vaccination, vaccination visits for these people should be postponed to avoid exposing healthcare personnel and other patients to the virus that causes COVID-19. When scheduling or confirming appointments for vaccination, patients should be instructed to notify the provider’s office or clinic in advance if they currently have or develop any symptoms of COVID-19.

Additionally, a prior infection with suspected or confirmed COVID-19 or flu does not protect someone from future flu infections. The best way to prevent seasonal flu is to get vaccinated every year.

The potential for asymptomatic spread of the virus that causes COVID-19 underscores the importance of applying infection prevention practices to encounters with all patients, including physical distancing (at least 6 feet) when possible, respiratory and hand hygiene, surface decontamination, and source control while in a healthcare facility. Immunization providers should refer to the guidance developed to prevent the spread of COVID-19 in healthcare settings, including outpatient and ambulatory care settings.

To help ensure the safe delivery of care during vaccination visits, providers should:

  • Minimize chances for exposures, including steps such as these:
    • Screen patients for symptoms of COVID-19 and contact with persons with possible COVID-19 prior to and upon their arrival at the facility, and isolate symptomatic patients as soon as possible.
    • Limit and monitor points of entry to the facility and install barriers, such as clear plastic sneeze guards, to limit physical contact with patients at triage.
    • Implement policies for adults and children over the age of 2 years to wear cloth face coverings (if tolerated).
    • Ensure patients practice respiratory hygiene, cough etiquette, and hand hygiene.
  • Ensure all staff adhere to the following infection prevention and control procedures:
    • Follow Standard Precautions, which include guidance for hand hygiene and cleaning the environment between patients.
    • Wear a medical facemask at all times.
    • Use eye protection based on level of community transmission of the virus that causes COVID-19:
      • Moderate-to-substantial transmission: Healthcare providers should wear eye protection given the increased likelihood of encountering asymptomatic COVID-19 patients.
      • Minimal-to-no transmission: Universal eye protection is considered optional, unless otherwise indicated as a part of Standard Precautions.
  • Consider these additional steps during vaccine administration:
    • Intranasal or oral vaccines:
      • Healthcare providers should wear gloves when giving intranasal or oral vaccines because of the increased likelihood of coming into contact with a patient’s mucous membranes and body fluids. They should change their gloves and wash their hands between patients.
      • Giving these vaccines is not considered an aerosol-generating procedure and thus, the use of an N95 or higher-level respirator is not recommended.
    • Intramuscular or subcutaneous vaccines:
  • For patients (sick or well) presenting for care or routine visits, ensure physical distancing by implementing strategies, such as:
    • Separating sick from well patients by scheduling these visits during different times of the day (e.g., well visits in the morning and sick visits in the afternoon), placing patients with sick visits in different areas of the facility, or scheduling patients with sick visits in a different location from well visits (when space is available).
    • Reduce crowding in waiting areas by asking patients to remain outside (e.g., stay in their vehicles, if applicable) until they are called into the facility for their appointment.
    • Ensure that physical distancing measures, with separation of at least 6 feet between patients and visitors, are maintained during all aspects of the visit, including check-in, checkout, screening procedures, and postvaccination monitoring. Use strategies such as physical barriers, signs, ropes, and floor markings.
    • Use electronic communications as much as possible (e.g., filling out needed paperwork online in advance) to minimize patients’ time in the office as well as their sharing of materials (e.g., clipboards, pens).

Yes. Guidance has been developed for giving vaccines at pharmacies, temporary, off-site, or satellite clinicspdf iconexternal iconpdf iconexternal icon, and large-scale influenza clinics. Other approaches to vaccination during the COVID-19 pandemic may include drive-through immunization services at fixed sites, curbside clinics, mobile outreach units, and home visits.

The general principles outlined for healthcare facilities should also be applied to alternative vaccination sites, with additional precautions for physical distancing that are particularly relevant for large-scale clinics, such as:

  • Providing specific appointment times or other strategies to manage patient flow and avoid crowding.
  • Ensuring sufficient staff and resources to help move patients through the clinic as quickly as possible.
  • Limiting the overall number of patients at any given time, particularly for populations at higher risk for severe illness from COVID-19.
  • Setting up a one-way flow through the site and using signs, ropes, or other measures to direct patient traffic and ensure physical distancing between patients.
  • Arranging a separate vaccination area or separate hours for persons at increased risk for severe illness from COVID-19, such as older adults and persons with underlying medical conditions, when feasible.
  • Selecting a space large enough to ensure a minimum distance of 6 feet between patients in line or in waiting areas for vaccination, between vaccination stations, and in postvaccination monitoring areas (the Advisory Committee on Immunization Practices recommends that providers consider observing patients for 15 minutes after vaccinationpdf iconpdf icon to decrease the risk for injury should they faint).

Influenza vaccination should be deferred until a patient is no longer acutely ill. This may be different for patients who are already being cared for in a medical setting than it is for patients who are isolating at home. In a medical setting, the timing for vaccination is a matter of clinical discretion. In the outpatient setting, in general, patients who are isolating at home should wait until they meet criteria for leaving isolation (even if they have no symptoms) to come to a vaccination setting in order to avoid spreading COVID-19 to others in the vaccination setting. CDC has guidance for when you can be around others after having COVID-19.

Curbside and drive-through vaccination clinics may provide the best option for staff and patient safety during the COVID-19 pandemic. Read CDC’s guidance on drive-through vaccination clinics.

COVID-19 testing prior to administering an influenza vaccine is not necessary. However, people who are sick and are suspected of having COVID-19 but who are not already in a health care facility should not come to a vaccination clinic or a healthcare facility for an influenza vaccination, in order to prevent the spread of SARS-CoV-2 to others. Expanded guidance for influenza vaccination during the COVID-19 pandemic is available online: Additional Considerations for Influenza Vaccination of Persons in Healthcare Facilities and Congregate Settings During the COVID-19 Pandemic.

Information about coadministration of COVID-19 and other vaccines is available. (Redirect added July 20, 2021).

Testing and Treatment of Respiratory Illness when SARS-CoV-2 and Influenza Viruses are Co-circulating

While waiting on results of testing, sick non-hospitalized persons with respiratory symptoms should self-isolate at home. Even if people test negative for both viruses, they should self-isolate because of the potential for false negative testing results – depending upon what kind of test was done (antigen test, molecular test) and the level of SARS-CoV-2 and influenza transmission  in the community. Persons not hospitalized but who are at high-risk for complications from influenza should get antiviral treatment for influenza as soon as possible.

For hospitalized patients, empiric oseltamivir treatment for suspected influenza should be started as soon as possible regardless of illness duration, without waiting for influenza testing results. Get more information on testing and treatment when SARS-CoV-2 and influenza viruses are co-circulating.

CDC has developed clinical algorithms that can help guide decisions for influenza testing and treatment when SARS-CoV-2 and influenza viruses are co-circulating.

Influenza antiviral medications have no activity against SARS-CoV-2 viruses, nor do they interact with medications used for treatment of COVID-19 patients. If a patient who is at high risk for serious influenza complications is diagnosed with SARS-CoV-2 and influenza virus co-infection, they should receive influenza antiviral treatment.

Flu Surveillance Data Updates

CDC monitors flu deaths each week using death certificate data collected by the National Center for Health Statistics (NCHS). During previous flu seasons, NCHS mortality surveillance data were used to calculate the percentage of all U.S. deaths occurring each week that had pneumonia and/or influenza (P&I) listed as a cause of death on the death certificate. However, because of the ongoing COVID-19 pandemic, COVID-19 coded deaths were added to P&I to create the PIC (pneumonia, influenza and/or COVID-19) mortality classification. CDC has displayed PIC mortality in its FluView report since week 40 of 2020. However, in order to make these data more easily downloadable and interactive, CDC incorporated PIC mortality data into its FluView Interactive data dashboard, beginning with the release of the Week 6 (week ending February 13, 2021) FluView report. FluView Interactive is an online data dashboard that accompanies the FluView report. Using FluView Interactive, users can download flu data and view this data via detailed, interactive graphs, charts, maps, and other visualizations.