We get it: You've worked long and hard leading up to a big competition, and you don't want some freak incident—like a bad reaction or a sore arm—to screw up all that progress.
Then again, you don't want to forego the shot and end up with the flu (and a big fat case of I Told You So) while training or tapering. So we went to three fitness and flu experts and asked them what they'd do in your situation. Their advice: Get a flu shot, but not within 10 days of your race.
Athletes should get vaccinated because they're at risk for overtraining syndrome, which can decrease immunity thanks to the extra stress on their bodies, says Dr. Ricardo E. Colberg of the Andrews Sports Medicine and Orthopaedic Center in Birmingham, Alabama. "It puts them at risk of developing illness and infections, including a significantly higher risk of acquiring the flu virus," says Colberg.
Getting the shot might keep you from missing important training days due to illness, so it's worth considering in-season. However, says Sam Altstein, D.O., medical director at Beth Israel Medical Group in New York City, it's wise to avoid the shot—and your doctor’s office—in the 10 days preceding a major event or competition.
"People often come to their doctor’s office for their vaccine, but a doctor’s office tends to be filled with sick and contagious people," he says, "thereby potentially increasing the chances of getting sick."
Plus, if you're trying to avoid having the flu on race day itself, getting a shot one or two days beforehand won't do much good. It takes the immune system up to a week to develop a sufficient antibody response to the vaccine, so it doesn't offer instant protection. And there are potential performance-harming side effects.
While the flu vaccine cannot give you the flu, it has been associated with mild cold- or flu-like symptoms. Altstein says that a direct link between the shot and these symptoms has not been proven (it's more likely that people were already exposed to upper respiratory viruses the days before they got their shot), but it’s one more reason to avoid a race-week vaccination.
"If you are planning on a major event such as marathon or triathlon, even a mild illness could severely impact your performance and also possibly lead to a more intense illness or vaccine reaction," he says. Wheezing, for example, is rarely associated with the flu vaccine, but your risk may be higher if you've already caught a bug and don't yet realize it.
And then there’s the potential arm pain. While mild pain is common for a day or two, says Altstein, there's also a small chance that significant swelling or increased pain could affect performance.
You could nix this risk by asking for the nasal vaccine instead of the shot, but Altstein doesn't recommend it. Because the nasal vaccine uses a live flu virus, it's more likely to cause symptoms like sore throat and nasal congestion. It also has limited availability, so your doc or pharmacy may not have it in stock.
You're better off getting a shot and sucking up any discomfort for a couple of days. In almost all cases, he says, it won't affect your strength or mobility.
Bottom line: Get the shot at least 10 days before your competition, or wait until after the race. "I tell my athlete-patients to schedule their annual visits with me in their respective off-seasons," says Altstein, "so as to negate the impact of potential side effects from vaccines on their training."