There’s a lot of time during flu season to dodge germs. Influenza activity peaks from December to February, but it can easily stretch from November (or earlier) to March (or later). So if you had the flu already this year, you might feel like at least you got your turn out of the way.
Except it doesn’t exactly work that way. During these long flu season months, you could get the flu a second time. Yep, really.
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That’s because—stay with us here—there are four different types of the flu: influenza A, B, C, and D. Influenza A and influenza B cause the seasonal epidemics we’ve come to expect in the fall and winter, and there are different strains of each. When you get sick from one particular strain of flu virus, your body develops an immune response that will protect you from getting re-infected with the very same bug. “Your likelihood of getting the same flu again is lower,” explains Denise Pate, MD, internal medicine physician with Medical Offices of Manhattan. “However, you can become infected with a different strain, and the antibodies you formed from the first bout are not providing protection.”
As you’ve probably heard, this year’s particularly rough flu season is thought to be due to the fact that the 2018 flu shot is not all that effective against this year’s dominant strain of influenza A, H3N2. If you got the flu from this particular virus in, say, December, you could encounter another form of the bug—like H1N1 or influenza B—come February and get sick again. “It is not uncommon for there to be second waves of influenza B virus activity later in the flu season,” says Sonja Olsen, PhD, in the influenza division of the Centers for Disease Control and Prevention (CDC). “Right now, both the proportion of H1N1 and influenza B viruses in circulation is increasing.”
Cruel, isn’t it? At least getting the flu once doesn’t give you a higher risk of going in for a second round.
We’ve said it before and we’ll say it again: It’s not too late to get your flu shot. That applies even if you already had the flu once this season. “Despite getting the flu, you are still eligible and should get the flu vaccine,” Dr. Pate says. “This will provide added protection against the strain of the flu you had, in addition to protecting you from the other strains of influenza that are circulating.”
Hopefully, we’re nearing the end of flu season 2018 and you won’t have to worry about any of this for much longer (until next year, of course). But we’re not out of the woods yet, according to Olsen: “There are still several weeks of flu activity to come.”