2017-18 U.S. flu season could be bad; vaccine not very effective

This year’s flu season is expected to be worse than recent years due to the type of virus circulating in the United States and a relatively ineffective vaccine.

“What happened is, in the development of the vaccine, as we grow it in eggs, the virus itself mutated a bit, so that there was almost an accidental mismatch purely on the basis of the virus trying to adapt itself to growing in eggs, which is the way you make the vaccine,” said Dr. Anthony Fauci, director of the NIH’s National Institute of Allergy and Infectious Diseases.

The mutation is blamed for a vaccine that was only about 10% effective during Australia’s flu season. The same strains of influenza that went through the Southern Hemisphere are now moving through the United States.

The vaccine caused sneezing, post-nasal drip and even sinus infections in some of those that received it, but that doesn’t mean people should avoid the shot.

“We want to make sure people don’t get the wrong impression. It is still always, always better to get vaccinated against influenza than not to get vaccinated,” Fauci said.

To make matters worse, this year’s flu strains include a particularly nasty variant.

“Well, it’s an H3N2 … and we’re seeing now that the vast majority of the strains that are early-circulating now right now in the United States, about 83 percent of them are influenza A and, of those, about 78 percent of them are this H3N2, which historically is always the worse influenza, for example, than an H1N1,” Fauci explained. “It’s the one that tends to make people more severely ill.”

Those most at-risk for serious complications:

• Children younger than five, but especially children under two;
• Adults 65 and older;
• Pregnant women (and women up to two weeks postpartum);
• Residents of nursing homes and other long-term care facilities;
• American Indians and Alaskan Natives;
• Persons of any age with chronic medical conditions;
• Persons undergoing therapy, or with a condition that may weaken their immune systems;
• Persons caring for someone in these groups should also be vaccinated. Healthcare workers, household contacts of individuals at risk for complications from the flu, daycare and school workers.

Information on the influenza vaccine can be found at the CDC’s website, or call CDC at 1-800-CDC-INFO.

See where flu cases are on the CDC’s weekly national flu activity map.