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Flu season is here, and vaccine isn’t fully protective from some strains, CDC says

REUTERS/Brian Snyder
CDC officials announced that the current flu vaccine does not protect as well as had been hoped against some of the influenza A (H3N2) type viruses.

Influenza activity in Minnesota has risen sharply over the last couple of weeks, according to the Minnesota Department of Health.

So far this year, 87 Minnesotans have been hospitalized with the flu — including 18 during last week alone — and eight school districts in the state have reported flu outbreaks.

On Thursday, Minnesota health officials also reported the first death of the current flu season, a child. No details about the case have yet to be released, to protect the family’s identity.

Could be a tough season

Although it’s still too early to know for sure, we may be in for a tougher-than-normal flu season this winter, according to the Centers for Disease Control and Prevention (CDC).

In an advisory sent to physicians on Wednesday, CDC officials announced that the current flu vaccine does not protect as well as had been hoped against some of the influenza A (H3N2) type viruses, the most dominant ones in circulation so far this year.

Some strains of A (H3N2) have mutated since the vaccine was made, leaving this year’s vaccine effective against only about half of them. It would take at least four months for a new vaccine to be made — too long to be of help this flu season, CDC officials said.

The current vaccine is still a good match, however, for the remainder of the A (H3N2) viruses — and for other influenza viruses (H1N1 and influenza B strains) that are expected to be in circulation this year, according to the CDC.

Not surprising

The announcement from the CDC that the current vaccine is not fully effective against this year’s circulating strains of influenza does not surprise Michael Osterholm, director of the University of Minnesota’s Center for Infectious Disease Research and Policy (CIDRAP).

Studies have shown that “you can’t predict necessarily what the protection is going to be” for any flu vaccine in any particular year — even if the vaccine matches circulating viruses, he said in a phone interview with MinnPost on Thursday.

“In some cases where the match wasn’t good, the vaccine performed at least average or better,” he explained. “In some where the match was quite good, the vaccine had very poor performance.”

In 2012, Osterholm and his colleagues released a comprehensive report that found flu shots were only about 60 percent effective in preventing influenza in healthy adults aged 18 to 64, while data on the vaccine’s effectiveness for children aged 2 to 17 and for adults aged 65 and older was inconsistent.

A 60 percent effectiveness rate is much lower than the 90 to 95 percent effectiveness rate of childhood vaccines for measles, pertussis (whooping cough) and other diseases.

Osterholm has long been advocating for a more aggressive research effort to develop a truly effective influenza vaccine.

“It’s unfortunate that we don’t have better information about these vaccines,” he said. “But what’s really unfortunate is that we’re not that much closer to a game-changing vaccine.”

‘Most specific tool we have’

Being less-than-fully effective is not the same as being unsafe, however. And, as MDH officials stress, influenza can be a serious, even life-threatening illness.

“The best way to reduce your risk of serious illness is with vaccination,” said Kris Ehresmann, director of the MDH’s Infectious Disease Epidemiology, Prevention and Control division, in a press statement released Thursday. “While the vaccine won’t stop every case of flu, it is the most specific tool we have to prevent the disease.”

Health officials recommend the flu vaccine for everyone aged 6 months and older unless they cannot be vaccinated due to medical reasons. The vaccine is especially important, they stress, for people at high risk for serious complications from the flu, such as pregnant women, children aged 5 and younger, adults aged 65 and older, and people with asthma, heart disease or other chronic medical conditions.

Check with your doctor or clinic about getting this year’s vaccine. You can also locate a flu clinic near you through the MDH’s influenza website. Just select “Vaccine Clinic Look-Up” and enter your ZIP code.

Comments (1)

  1. Submitted by Pavel Yankovic on 12/05/2014 - 03:19 pm.

    And then…

    there is the misconception held by some that those who do get the flu despite being vaccinated would have had a more serious case of it had they not received the vaccine.

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