ATLANTA The novel H1N1 virus is expected to make a big impact in the coming cough/cold/flu season, though just by how much is hard to determine, noted Anne Schuchat, director of the National Center For Immunization and Respiratory Diseases for the Centers for Disease Control and Prevention, during a press conference held Friday.
Based on the course of the novel H1N1 virus in the spring, between 6% and 8% of people in those communities that were affected came down with the novel flu, at a time when seasonal flu incidence is relatively zero. “In a longer winter season, attack rates would probably reach higher levels than that,” Schuchat said. “Maybe two or three times as high as that.” During seasonal influenza in the winter, as many as15% of people develop influenza-like illness.
Worse-case scenario models used as pre-pandemic planning tools have accounted for as many as 40% of Americans to be infected, or to be tasked with caring for an infected relative, this fall — which is expected to cause mass absenteeism across schools and work forces.
“Much of our framing has been focused on the very severe impact where 40% of the workforce might be absent because they’re sick or staying home to care for a sick person,” Schuchat said, but that isn’t the most likely scenario. “Right now we’re not expecting that high an absentee rate, but we are expecting challenges.”
As of Friday, there were 43,771 confirmed novel H1N1 cases, including 302 deaths. But that case count is a far cry from accurately measuring the number of cases, Schuchat warned, especially as the number of states actually testing for the novel H1N1 virus drops.
“We believe there have been well over a million cases of the new H1N1 virus so far in The United States,” Schuchat said. “And the patterns that we’re seeing right now are 20 states reporting widespread or regional influenza activity. … It’s very unusual for that kind of illness to be occurring at this time of the year. The Novel H1N1 viruses are making up 98% of all the subtyped viruses we have, subtype influenza A viruses, and we’re seeing them dominate here in the U.S.”
The CDC also updated its vaccination recommendations Friday. “At this point, 83% of the population is recommended to get an annual flu vaccine and we recommend it for anyone who wants to reduce their risk of flu,” Schuchat said. “Unfortunately, only about 40% of the U.S. population received the flu vaccine last year, so we’re really recommending an intensifying use of this vaccine because it does protect against illness and complications like hospitalization and severe outcomes.”
Schuchat also stressed that health care workers need to get vaccinated, especially this year. “We recommend them strongly to receive the seasonal flu vaccine,” Schuchat said. “And I’m expecting when H1N1 vaccine recommendations come out it’s very, very likely health care workers will be in that group that ought to get vaccines as well.” Presently, CDC is estimating that enough novel H1N1 vaccine, if approved, may be ready by mid-October to sustain a national vaccination program.