On Wednesday, the CDC announced that the strain of influenza virus chosen as the basis of this year’s vaccine does not match the common strains of flu virus now circulating. On Thursday, the CDC warned of the severity of the upcoming flu season. David Muir interviewed ABC’s Chief Medical Editor Dr. Richard Besser on ABC World News (12/4, story 7, 1:15, Muir) about the CDC’s concerns over the flu. Muir reported that “Tonight, the CDC now pointing to what it calls a concerning sign that this flu season will be a bad one.” Dr. Besser explained that the makers of the flu shot “guessed wrong” in their selection of the virus to base the shot on. “Between the time they selected the strain for the vaccine in February and now, the flu strain in the community mutated. So, that the vaccine no longer provides protection,” he added. Besser explained that the shot is “not going to work the way a flu vaccine normally works. But it should provide some level of protection and some protection is better than none.” Besser said the flu season is “going to be severe for two reasons: one is, it’s a bad match. But the particular strain that’s in the community in past outbreaks has caused more severe disease, more people in the hospital.” The CBS Evening News (12/4, story 7, 0:25, Pelley) briefly reported, “The CDC told us today the flu shot that you got this year may not be as effective as you would hope … while flu vaccines are usually about 60 percent effective, this season it could be 40 percent.” NBC Nightly News’ (12/4, story 4, 1:35, Holt) Dr. Nancy Snyderman reported that “The CDC has issued a warning tonight about the flu virus… It has mutated, meaning that the flu shot or mist that millions of people got to protect themselves won’t provide nearly as much protection as usual.” Snyderman said that “it’s too late to make a new vaccine for this season, so people who think they may be getting the flu should see their doctor right away,” adding that “the most effective drugs…work best in the first 48 hours of getting sick.”
In continuing coverage from yesterday’s announcement, the Washington Post (12/5, Bernstein) reports that “the government on Thursday recommended immediate vaccination for anyone who hasn’t taken that precaution and urged people who come down with the flu to seek anti-viral medication from their doctors.” According to the CDC announcement, five children have already died this year from the flu, and the strain of the virus circulating, H3N2, has been indicative of a severe flu season in three of the last 11 seasons. The strain has led to increased deaths and hospitalizations in past years. Dr. Thomas Frieden of the CDC noted that only one of every six people suffering from the flu get antivirals, saying those drugs “aren’t a substitute for vaccine. Vaccine prevents flu, but anti-virals are an important second line of defense … and this year treatment with anti-viral drugs is especially important.”
While the H3N2 flu strain is the dominant variety, three other strains are also circulating, according to USA Today (12/5, Szabo). The H3N2 strain “has doubled rates of hospitalizations and deaths in the past, especially among older people, very young children and people with chronic health conditions, said Frieden.”
The New York Times (12/5, Mcneil, Subscription Publication) adds that Frieden said “Flu is unpredictable, but what we’ve seen thus far is concerning.” Though H3N2 is not the only strain of virus circulating, the Times writes that “91 percent of the approximately 1,200 samples tested thus far are of the H3N2 subtype of influenza A, Dr. Frieden said,” and “almost all the rest were influenza B.” The Times notes that none of the strains seen so far are descendants of the swine flu virus. Of the H3N2 samples, 45% were of the subtype against which this season’s flu shot does not protect.
The Wall Street Journal (12/5, Mccabe, Subscription Publication) writes that the flu virus mutation has “drifted,” according to the CDC. Dr. Frieden said, “Getting a vaccine that provides at least partial protection may be more important than ever.”
The Los Angeles Times (12/5, Morin) explores the process of developing the flu shot. Because of the delay between when the flu vaccine has to be manufactured and when it is actually administered, the flu virus has ample opportunity to mutate or drift. Manufacturing begins four to six months before the flu season takes off, meaning scientists must guess or predict which virus strain will be dominant.