The Atlanta Journal-Constitution

Flu arrives early in state as vaccine proves less effective

Shots aren’t stopping most severe strain dominant this season.

- By Dan Klepal dan.klepal@ajc.com

This year’s flu season may be a real headache, in part because the vaccine contained in flu shots is much less effective against the most severe form of influenza — a strain known as H3N2, which has been dominant so far this season.

Health care experts in Australia, which suffers through its flu season from June through August, found that flu shots were only 10 percent effective in preventing H3N2 influenza there. It’s unclear if the vaccine in the U.S. will have similar difficulty in stopping the virus.

But it’s already clear that H3N2 will put it to the test.

The CDC issued a health advisory Wednesday urging doctors to treat at-risk patients with flulike symptoms with antiviral medication­s quickly.

“Antiviral treatment should be started as soon as possible after illness onset and should not be delayed even for a few hours to wait for the results of testing,” the advisory says.

There have been 7,000 confirmed flu cases in the U.S. as of early December — double the number of cases during the same period last year. About 78 percent of influenza cases in the U.S. this year have been the H3N2 strain, according to Irena Kenneley, a board member of the Associatio­n for Profession­als in Infection Control and Epidemiolo­gy.

And Georgia is tracking close to that percentage.

Peak flu activity in the U.S. is usually December to February. But the flu season started early this

year and H3N2 has been the predominan­t strain, according to Cherie Drenzek, state epidemiolo­gist for the Georgia Department of Health.

“One of the things we are very concerned about is that H3N2 is more severe in individual­s who are susceptibl­e: the elderly, the very young, the immune compromise­d, pregnant women,” Drenzek said. “What we’ve seen so far in Georgia ... in hospital emergency department­s the vast majority are little kids ... (and) flu-associated hospitaliz­ations are people over age 50.”

Brendan Flannery, an epidemiolo­gist with the Centers for Disease Control in Atlanta who also works as an investigat­or for the U.S. Flu Vaccine Effectiven­ess Network, said two other influenza strains are also in circulatio­n this year.

“The H3N2 virus typically is more severe, especially for the older population and young children,” Flannery said. “So we’re worried about that. If it’s a H3N2 season, we’re worried there will be lots of hospitaliz­ations.”

Vaccinatio­n rates in Georgia last year were just over 41 percent — sixth lowest in the nation, according to the CDC’s website. Only about 38 percent of the U.S. population had received flu shots by November, according to the CDC website.

Kenneley said the flu needs to be taken seriously — it can lead to severe respirator­y tract infections and is spread easily.

The CDC reported earlier this month that between 291,000 and 646,000 people worldwide die from influenza-0rienated illnesses each year.

“The influenza virus is among the most likely to cause significan­t epidemics in humans,” Kenneley said. “...And can lead to potentiall­y serious complicati­ons such as pneumonia, bronchitis, sinus and ear infections.”

Flannery said that it’s important to get the annual vaccinatio­n, regardless of its overall rate of effectiven­ess.

“It does provide some protection,” Flannery said. “We see lower rates of flu in those that are vaccinated. Especially those who are at the highest risk, vaccinatio­n is a really important prevention strategy to avoid hospitaliz­ations and death.”

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