CDC: H1N1 is Dominating Flu Season, Hitting Younger People Hard

The Centers for Disease Control (CSC) recently released data showing that 99 percent of individuals who tested positive for flu this season had contracted influenza A,  the H1N1 virus. CDC Director Dr. Tom Frieden and National Center for Immunization and Respiratory Diseases (NCIRD) Director Dr. Anne Schuchat recently gave a telebriefing, updating the public on flu activity and vaccine effectiveness estimates within the U.S. “So far this season, we have seen flu hitting middle-age and younger adults hard,” stated Dr. Frieden. “The season is likely to continue for several more weeks, especially in parts of the country where flu activity started later in the season.”

U.S. influenza vaccines were proven to be 62 percent effective for H1N1 virus prevention, according to a Morbidity and Mortality Weekly Report. However, “by November, only a third of 18 to 64 year olds had been vaccinated,” stated Dr. Schuchat during the telebriefing. “That’s one of the reasons we’re seeing a much higher proportion of hospitalizations and deaths among 18 to 64 year olds than we generally see.” In comparison, the vaccination rate among seniors was at 60 percent by November, 2014, and at 50 percent for young children. “Vaccine effectiveness point estimates range from 52 percent for people 65 and older to 67 percent for children 6 months to 17 years of age,” noted Schuchat. Consequently, the CDC urges that everyone six months and older receive the annual flu vaccine, including pregnant women and individuals at high risk of flu complications.

According to Dr. Frieden and Dr. Schuchat, one reason the H1N1 virus  re-emerged this season is that too few people have been immunized. “Young children, infants born after the H1N1 pandemic in 2009, have not been exposed to it. So we have a cohort of young children, albeit many of them now vaccinated, but many of them not, who are susceptible to H1N1,” said Dr. Frieden. “Also, there may be some pooling or declining susceptibility or declining immunity, rather, in society as a whole.” Dr. Schuchat agreed, noting “we think that what happens is a mixture of population immunity, vaccine coverage, and probably mystery factors that we just don’t understand.”

Although the vaccines have proven effective for preventing flu and are available to the public, younger people are not getting them. “So I think that it is important to know that this year we had vaccines before high rates of disease were circulating and we think that’s a principle difference in how the season is evolving here compared to 2009,” said Dr. Schuchat. “We just wish more people would get vaccinated.”

So far this year, approximately 134 million doses of flu vaccine were distributed, and companies are expecting to make roughly 138 million more. However, it may be difficult for people to find the vaccine near their location. Dr. Schuchat noted that there are tools available to the public on the Internet to locate where flu vaccines are. While flu-related deaths range from 4,000 to 50,000 per year in the U.S., Dr. Schuchat stated, “the more people we vaccinate, the fewer deaths we think we’ll have.”