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December 2010 Influenza E-Brief

CDC Influenza E-Brief Logo

CDC Influenza E-Brief
December 2010 Edition

National Influenza Vaccination Week -- December 5-11, 2010

man blowing nose

Each year during National Influenza Vaccination Week (NIVW), the importance of influenza vaccination throughout the entire October—May influenza season is highlighted. Influenza vaccination is the best way to prevent influenza and its severe complications. This year, the new universal recommendations from the Advisory Committee for Immunization Practices (ACIP) means routine vaccination for everyone six months and older. NIVW will reinforce this recommendation and emphasize the need for vaccination of several groups at high risk of serious complications from influenza infection.

Throughout the week of December 5-11, 2010, the Department of Health and Human Services, Centers for Disease Control and Prevention (CDC), and other agencies will be working with health partners to highlight the importance of influenza vaccination. Each day, messages and activities will be directed to a different group; however, everyone is encouraged to get vaccinated as soon as they can to help prevent the flu. On December 6, events will highlight the importance of vaccination for the whole family — the emphasis will be on pregnant women, children, and caregivers of infants aged <6 months. On December 7, events will highlight the importance of vaccination for persons with chronic health conditions (particularly those with asthma, diabetes, heart disease, kidney and liver disorders, neurological disorders, blood disorders, morbid obesity, HIV or AIDS, or cancer) that put them at increased risk for serious influenza-related complications. December 8 events will highlight employee health, with a special emphasis on people working in health care settings who are at risk of getting and spreading flu. December 9 events will highlight older adults (particularly those aged 65 and older), and December 10 will highlight young adults who were disproportionately affected during the 2009 H1N1 pandemic.

Influenza vaccination education and awareness multi-media materials are available free for download at . For more information about NIVW and how you can get involved, please visit the National Influenza Vaccination Week website.

Help encourage your friends and family to protect themselves and their communities. Everyone can fight the flu—vaccination is the most important step. To find out where you can get the flu vaccine, please use the Flu Vaccine Finder.

Situation Update: Summary of Weekly US Influenza Surveillance Report

According to the November 29, 2010 FluView report for the week of November 14-20, 2010, influenza activity remained low in the United States overall, but increased slightly in the southeast U.S. compared to the previous week’s report. The percentage of viruses testing positive for influenza nationally continued to increase, led by sharp increases in the southeast region of the country. This increase in the number of specimens testing positive for influenza is an early signal that flu activity is picking up. In most years, influenza activity doesn’t peak until January or February, although the timing of peak influenza activity can vary from year to year and occur anytime from late fall to early spring.

Visits to doctors for influenza-like illness (ILI) continue to be low nationally. All 10 U.S. regions continue to report ILI below region-specific baseline levels; however, ILI levels are rising in Region 4 (AL, FL, GA, KY, MS, NC, SC, and TN). One state (Georgia) reported high ILI activity, and two states (Oklahoma and West Virginia) reported low ILI activity. New York City and 47 states reported minimal ILI activity, and insufficient data were available to determine an ILI activity level for the District of Columbia.

FluView is available – and past issues are archived – on the CDC website at

To date, more than 160 million doses of influenza vaccine have been distributed:

woman with baby


Condition: Flu Fatigue (floo fuh-teeg)

Symptoms: Symptoms of Flu Fatigue include an unwillingness to seek influenza vaccination; a perception that we are not at risk for another influenza pandemic because the world just experienced the 2009 H1N1 influenza pandemic; a misunderstanding that the next influenza pandemic would be no worse than the last one in terms of severity of sickness and number of deaths; a failure to engage in preventive measures to protect against seasonal flu; and a decreased focus on pandemic preparedness.

Dangers of Flu Fatigue: Flu seasons are unpredictable and can be severe. Over a period of 30 years, between 1976 and 2006, estimates of flu-associated deaths range from a low of about 3,000 to a high of about 49,000 people. An unvaccinated public is at greater risk for these outcomes and other flu-related complications. A failure to continue pandemic preparedness efforts and capitalize on lessons learned during the H1N1 response could prove hazardous in the event of another flu pandemic.

Treatment: All individuals age 6 months and older should get vaccinated against the flu and follow other CDC prevention guidelines. Opinion leaders should encourage people to remain vigilant in preparing for pandemic influenza events. Public health and preparedness stakeholders should leverage lessons from the 2009 H1N1 pandemic to ensure that we are well protected against seasonal influenza and prepared for the next influenza pandemic.

North American Plan for Avian and Pandemic Influenza (NAPAPI)

CDC is participating in an interagency work group on updating the 2007 North American Plan for Avian and Pandemic Influenza (NAPAPI) with counterparts from Canada and Mexico. The purpose is to identify and strengthen trilateral coordination of pandemic influenza planning and response, using lessons from the 2009 H1N1 influenza pandemic. CDC participated on a Trilateral Workshop in Washington, D.C. on November 2nd and 3rd to discuss specific areas for improvements and plan for upcoming ministerial meetings in 2011. Topics included communications and public messaging, surveillance, epidemiology and laboratory practices, vaccines and antivirals, border control measures, animal and human health interface, and resiliency of critical preparedness and response.

Pandemic Influenza Scientific Agenda (PISA)

Despite the many successes of CDC’s 2009 H1N1 influenza Response, critical knowledge gaps about influenza contributed to difficulty in developing evidence-based prevention and control strategies. Given the need for additional evidence to guide public health efforts, CDC quickly undertook an initiative to identify and fill these gaps. The result is the Pandemic Influenza Scientific Agenda (PISA) Program initiative, which consists of 23 scientific projects conducted by CDC Principal Investigators. $40 million in H1N1 supplemental funds have been invested in the 23 projects, which cover topics ranging from influenza transmission, to upgrading CDC’s laboratory science to better address pandemic influenza, and analyzing the impact of social media on pandemic influenza communications efforts. On December 3, 2010 PISA investigators presented their projects and are fostering collaborative relationships to leverage scientific advances.

Some PISA Projects Include:

  • Factors Influencing the Transmission of Influenza: Examines the persistence of influenza virus in aerosols to better understand transmission of influenza in healthcare settings. The project will determine whether viable influenza virus is present in aerosols collected by personal aerosol samplers; which medical procedures generate aerosols, and; the number, size, distance traveled, and point of deposit of potentially infectious droplets and aerosol particles generated during a cough.
  • Comparison of N95 Respirators and Surgical Masks Effectiveness for Influenza: Evaluate whether the incidence of influenza and other respiratory infections is different among healthcare workers who wear respirators vs. surgical masks for the duration for their work shifts in an outpatient setting.
  • Persistence and Infectivity of the Influenza H1N1 Virus on Personal Protective Equipment and Surfaces: Study the length of time influenza virus remains infectious on various surfaces, to better address questions about extended use and re-use of N-95 respirators; ultraviolet disinfection of environmental surfaces; and, hand hygiene interventions.
  • Virologic Evaluation of the Modes of Influenza Virus Transmission among Humans: Assess the relative contribution of different modes of influenza virus transmission (contact transmission, large droplet transmission and droplet nuclei transmission) among humans, to better define duration of influenza viral shedding; understand influenza virus environmental contamination during human infection; and, ascertain the distance between people that poses a risk for influenza virus transmission.

Reports of Human Infections with Swine Origin Influenza A (H3N2)

In the November 12, 2010 FluView, a weekly US influenza surveillance report, CDC reported two human infections with swine origin influenza A (H3N2) viruses in the United States. Test samples from two patients submitted by Wisconsin and Pennsylvania were confirmed at CDC as positive for swine origin triple-reassortant (tr) H3N2 influenza viruses—viruses that normally infect pigs. While human infection with swine influenza viruses is rare, it can occur. This is most likely to occur when people are in close proximity to infected pigs, such as in pig barns and livestock exhibits housing pigs at fairs. Ongoing investigations in both states have shown no evidence of community transmission of these viruses. The most likely scenario at this point is that these are two isolated cases of human infection with swine influenza viruses that, while rare, are detected from time to time. While both patients have fully recovered from their illnesses, these two cases underscore the importance of human and animal influenza surveillance. These two cases bring the total number of human infections with swine origin influenza viruses reported to CDC since 2005 to 18.

Although the vast majority of instances of human infection with animal influenza viruses do not result in human to human transmission, each case should be fully investigated to be sure that such viruses are not spreading among humans and to limit further exposure of humans to infected animals if infected animals are identified. Surveillance for both seasonal and novel influenza viruses is conducted by the CDC and its state and local health partners year round.

More information about these two recent human cases of swine origin influenza A (H3N2).

More information about swine influenza.

Scientific Workshop on Understanding Influenza Transmission

Although flu viruses were first identified nearly 80 years ago, major questions remain regarding how flu viruses are most often spread. Reports from the Institute of Medicine in 2007 and 2009 identified improved understanding of flu transmission as a high priority for developing science-based recommendations to prevent the spread of pandemic and seasonal flu in healthcare settings. A better understanding of flu transmission is also needed to improve recommendations in other settings such as schools, work, and mass transportation.

On November 4th and 5th, CDC hosted a workshop entitled, “Update on Approaches to Understanding Human Influenza Transmission.” The workshop provided an opportunity for scientists in public health, academia and government to review current information on influenza transmission, to identify scientific gaps in understanding the modes of influenza transmission, and to discuss the best scientific approaches to better understand how influenza viruses are transmitted to help resolve continuing questions about the relative contributions of contact, droplet, and airborne transmission in humans.

Participants with backgrounds ranging from infection control, industrial hygiene, aerobiology, mathematical modeling, and influenza epidemiology, virology and pathogenesis participated in the meeting. Information was provided on the properties of the virus and environmental factors, such as temperature, humidity, air movement and ultraviolent light, that may impact transmission. There were also reports of human studies on influenza transmission, the use of masks, respirators and hand hygiene to prevent transmission and what we can learn about transmission from outbreak investigations . Participants then discussed possible scientific approaches that would improve understanding of the relative contribution of the different modes of influenza transmission. A summary of the meeting will be posted on the CDC website. (Link will be shared in the next e-brief edition).

  • Page last reviewed: December 6, 2010
  • Page last updated: December 6, 2010
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