Interpretive Summary for December 10, 2021
On November 26, 2021, the World Health Organizationexternal icon (WHO) classified a new variant, B.1.1.529, as a Variant of Concern (VOC) and named it Omicron. On November 30, 2021, the United States also classified it as a VOC. On December 1, 2021, CDC announced that the first confirmed case of the Omicron variant had been detected in the United States. As of December 9, 2021, 23 states have announced cases of the Omicron variant.
A new CDC report summarizes what’s known about initial cases of COVID-19 infection with the Omicron variant in the United States and prevention strategies to slow the spread. While Omicron viruses have been detected, the Delta variant still currently accounts for over 99.9% of all circulating SARS-CoV-2 viruses in the United States.COVID-19 vaccination, along with consistent use of prevention strategies, remains the best tool we have to protect people from COVID-19, slow transmission, and reduce the likelihood of new variants emerging. CDC recommends that:
- Everyone 5 years and older protects themselves by getting fully vaccinated.
- Everyone ages 18 years and over gets a COVID-19 booster dose.
- Teens 16–17 years old who received Pfizer-BioNTech COVID-19 vaccines can get a booster dose.
- Immunocompromised people talk with their healthcare professional about additional primary doses and booster doses following the primary series.*
As the weather gets colder and people gather indoors, getting a COVID-19 vaccine or booster dose can help protect you, the people around you, and the people you love. To find a COVID-19 vaccine provider near you, visit vaccines.gov or your state or local public health department website.
*Immunocompromised people have special considerations for vaccination, including additional primary dose and booster dose recommendations following the primary series. For more information, visit CDC’s website.
Note to readers: Self-testing (also known as home or over-the-counter testing) is another way to prevent the spread of COVID-19. You can self-test before an indoor gathering with people who don’t live in your household, regardless of your vaccination status or if you have symptoms.
- COVID Data Tracker’s Pregnant People: COVID-19 Illness and Outcomes tab now includes new visualizations showing COVID-19 deaths among pregnant people by month and ICU admissions among pregnant people with COVID-19 by month.
- COVID Data Tracker’s Vaccination Trends tab now includes booster dose trends by jurisdiction.
- COVID Data Tracker’s County View tab now includes pediatric vaccination data (for people 5 years and older) at the county level.
- COVID Data Tracker’s Nursing Home COVID-19 Vaccination Data Dashboard now includes data on weekly COVID-19 additional and booster dose vaccinations.
- SARS-CoV-2 B.1.1.529 (Omicron) Variant — United States, December 1–8, 2021
- Booster and Additional Primary Dose COVID-19 Vaccinations Among Adults Aged ≥65 Years — United States, August 13, 2021–November 19, 2021
- BioNTech COVID-19 Vaccines among Hospitalized Veterans — Five Veterans Affairs Medical Centers, United States, February 1–September 30, 2021
- Community-Based Testing Sites for SARS-CoV-2 — United States, March 2020–November 2021
The current 7-day moving average of daily new cases (118,515) increased 37.3% compared with the previous 7-day moving average (86,315). A total of 49,458,520 COVID-19 cases have been reported in the United States as of December 8, 2021.
Currently two variants, Omicron and Delta, are classified as Variants of Concern (VOC) in the United States. CDC’s COVID Data Tracker shows that the Omicron variant currently accounts for less than 0.1% of variants circulating in the United States. Delta remains the predominant variant in the United States. Nowcast projections* for the week ending December 4, 2021, estimate the national and regional proportions of Delta to be greater than 99%.
CDC has been actively monitoring and preparing for the Omicron variant and will continue to work with other U.S. and global public health and industry partners to learn more. For more information on variant proportions, visit COVID Data Tracker.
Total Cases Reported
Current 7-Day Average**
Prior 7-Day Average
Change in 7-Day Average since Prior Week
* The median time from specimen collection to sequence data reporting is about 3 weeks. As a result, weighted estimates for the most recent few weeks may be unstable or unavailable. CDC’s Nowcast is a data projection tool that helps fill this gap by generating timely estimates of variant proportions for variants that are circulating in the United States. View Nowcast estimates on CDC’s COVID Data Tracker website on the Variant Proportions page.
** Historical cases are excluded from daily new cases and 7-day average calculations until they are incorporated into the dataset for the applicable date. Of 348,270 historical cases reported retroactively, 126 were reported in the current week and 574 were reported in the prior week.
The U.S. COVID-19 Vaccination Program began December 14, 2020. As of December 9, 2021, 477.4 million vaccine doses have been administered. Overall, about 237.5 million people, or 71.5% of the total U.S. population, have received at least one dose of vaccine. About 200.7 million people, or 60.5% of the total U.S. population, have been fully vaccinated.* About 49.9 million additional/booster doses in fully vaccinated people have been reported. As of December 9, 2021, the 7-day average number of administered vaccine doses reported (by date of CDC report) to CDC per day was 1,855,455, a 29.9% increase from the previous week.
CDC’s COVID Data Tracker Vaccination Demographic Trends tab shows vaccination trends by age group. As of December 9, 2021, 95.0% of people ages 65 years or older have received at least one dose of vaccine and 87.0% are fully vaccinated. More than three-quarters (83.9%) of people ages 18 years or older have received at least one dose of vaccine and 71.8% are fully vaccinated. For people ages 12 years or older, 81.9% have received at least one dose of vaccine and 70.1% are fully vaccinated. For people ages 5 years or older, 76.0% have received at least one dose of vaccine and 64.3% are fully vaccinated.
People who received at least one dose
People who are fully vaccinated*
Percentage of the U.S. population that has received at least one dose
Percentage of the U.S. population that has been fully vaccinated*
Percentage point increase from last week
Percentage point increase from last week
*Represents the number of people who have received the second dose in a two-dose COVID-19 vaccine series (such as the Pfizer or Moderna vaccines) or one dose of the single-shot Johnson & Johnson’s Janssen vaccine.
New Hospital Admissions
The current 7-day daily average for December 1–December 7, 2021, was 7,441. This is a 15.9% increase from the prior 7-day average (6,419) from November 24–November 30, 2021.
Total New Admissions
Current 7-Day Average
Prior 7-Day Average
Change in 7-Day Average
The start of consistent reporting of hospital admissions data was August 1, 2020.
Daily Trends in Number of New COVID-19 Hospital Admissions in the United States
New admissions are pulled from a 10 am EST snapshot of the HHS Unified Hospital Timeseries Dataset. Due to potential reporting delays, data from the most recent 7 days, as noted in the figure above with the grey bar, should be interpreted with caution. Small shifts in historic data may also occur due to changes in the Centers for Medicare and Medicaid Services (CMS) Provider of Services file, which is used to identify the cohort of included hospitals.
COVID-NET: Hospitalization Rates by Vaccination Status in Adults
CDC’s Coronavirus Disease 2019-Associated Hospitalization Surveillance Network (COVID-NET) shows that through October 2021, rates of COVID-19-associated hospitalizations are higher in unvaccinated adults compared to fully vaccinated adults regardless of age. The age-adjusted COVID-19-associated hospitalization rate among adults ages 18 years and older was 8 times higher in unvaccinated people than those who were vaccinated. Age-specific rates of COVID-19-associated hospitalizations are 13 times higher among unvaccinated adults ages 18-49 years, 11 times higher among unvaccinated adults ages 50–64 years, and 6 times higher among unvaccinated adults ages 65 years and older.
Hospitalization Rates by Vaccination Status in Adults
The Coronavirus Disease 2019 (COVID-19)-Associated Hospitalization Surveillance Network (COVID-NET) is an additional source for hospitalization data collected through a network of more than 250 acute-care hospitals in 14 states (representing ~10% of the U.S. population). Detailed data on patient demographics, including race/ethnicity, underlying medical conditions, medical interventions, and clinical outcomes, are standardized case reporting form.More COVID-NET Data
The current 7-day moving average of new deaths (1,092) has increased 27.8% compared with the previous 7-day moving average (854). As of December 8, 2021, a total of 790,766 COVID-19 deaths have been reported in the United States.
Total Deaths Reported
Current 7-Day Average*
Prior 7-Day Average
Change in 7-Day Average Since Prior Week
* Historical deaths are excluded from the daily new deaths and 7-day average calculations until they are incorporated into the dataset by their applicable date. Of 14,968 historical deaths reported retroactively, 407 were reported in the current week; and 230 were reported in the prior week.
The percentage of COVID-19 NAATs (nucleic acid amplification tests)* that are positive (percent positivity) is stable in comparison to the previous week. The 7-day average of percent positivity from NAATs is now 7.5%. The 7-day average number of tests reported for November 26 – December 2, 2021, was 1,328,837, up 7.8% from 1,232,562 for the prior 7 days.
Total Tests Reported
Total Tests Reported
7-Day Average Tests Reported
7-Day Average % Positivity
Total Tests Reported
Previous 7-Day Average % Positivity
Percentage point change in 7-Day Average % Positivity since Prior Week
*Test for SARS-CoV-2, the virus that causes COVID-19
A Closer Look Section presents more detailed information for readers who want to learn more about current issues of interest.
State of the Pandemic – Fall 2021
In the United States, the SARS-CoV-2 pandemic has produced 5 waves of new cases. The peaks of those waves were on April 9, 2020 (34,893 cases), July 17, 2020 (78,252 cases), January 6, 2021 (295,378 cases), April 7, 2021 (79,302 cases), and September 1, 2021 (192,211 cases). The first peak likely under-represented the true case incidence because the availability and use of testing was limited at that early point in the pandemic. The third peak, in January 2021, was the highest. The recent fifth peak, in September 2021, was more than 100,000 cases lower than the January 2021 peak. Although the burden of severe illness was high with large numbers of hospitalizations and deaths in the most recent wave, both were much lower than in the third wave. Population immunity levels, both from vaccination and from previous infection, likely limited the impact of the virus during the fifth wave.
Nationally, surveillance indicators tracking levels of SARS-CoV-2 circulation and associated illnesses, hospital admissions, and deaths began declining in early September 2021, and continued into October 2021. As the weather began to get colder and people started to spend more time indoors, we started to see an increase in cases and hospitalizations in November 2021. On December 8, 2021, the current 7-day moving average of new cases nationwide was 118,515, up 37.3% from the previous week. The 7-day average of new hospital admissions was 7,441, up 15.9% from the previous week. The 7-day moving average of new deaths nationwide was 1,092, up 27.8% from the previous week.
As of December 9, 2021, over 237 million people (71.5% of the US population) have been fully vaccinated. Older adults have the highest vaccination rates of any age group: 87.0% of people ages 65 years or older are fully vaccinated. As of December 9, 2021, 17.9% of people ages 5 through 11 years old have received at least one dose of vaccine and 7.0% of people ages 5 through 11 years old are fully vaccinated. CDC recommends that people with compromised immune systems receive an additional dose of an mRNA COVID-19 vaccine.
For people who received a primary series of an mRNA COVID-19 vaccine, booster doses are recommended at least six months after completing the primary series for everyone ages 18 years and older. Everyone ages 18 years and older who received the Johnson & Johnson/Janssen vaccine should get a booster shot at least two months after receiving the primary shot. On December 9, 2021, the U.S. Food and Drug Administration authorized the use of a single booster dose for adolescents ages 16 and 17 years at least six months after completion of a primary series with the Pfizer-BioNTech COVID-19 vaccine. That same day, CDC strengthened its booster dose recommendations and now encourages everyone 16 years and older to receive a booster dose. At this time, only the Pfizer-BioNTech COVID-19 vaccine is authorized and recommended for adolescents ages 16 and 17 years. Since August 2021, over 49.9 million fully vaccinated people have received a booster dose; 26.9% of those ages 18 years or older and 49.1% of those ages 65 years or older who are fully vaccinated have received a booster dose.
A new SARS-CoV-2 variant, named Omicron by the World Health Organization, was classified on November 30, 2021, as a Variant of Concern by the U.S. government SARS-CoV-2 Interagency Group. The first U.S. case of the Omicron variant was confirmed on December 1, 2021, and has now been detected in a number of states. CDC is working with state and local public health officials to monitor the spread of the new variant. CDC is also working with its public health partners to determine how easily the variant is transmitted, the severity of disease caused by the variant, and how well vaccines and therapeutics will work against the variant. However, the emergence of this variant and the fact that the Delta variant continues to be the most dominant variant present in the United States, reinforces the need for people to get vaccinated and for those fully vaccinated to receive boosters.
As the country approaches the winter—typically the high season for respiratory viruses like SARS-CoV-2 and influenza — there are many unknowns. Continuing to monitor case rates and the burden of COVID-19 illnesses and hospitalizations will be key to responding quickly and effectively in the coming months to limit illness and keep our health systems functioning for all people. COVID-19 vaccination is crucial to controlling the pandemic as it provides substantial protection against infection, hospitalization, and death. As we approach the holiday season, a time when gatherings of friends and families are common, it is important to maintain prevention measures and ensure protection of those most vulnerable.