The pharmacy chain pitches started in August: Come in and get your flu shot.
Not that long ago, most flu-shot campaigns started as the leaves began to turn in October. But the rise of retail medical clinics inside drug stores over the past decade has stretched the flu-shot season. The marketing of the vaccine starts when the shots become available in August and lasts as long as the supply, often into April or May.
That’s even though the start of flu season is weeks – if not months – away.
Some experts say the marketing may be overtaking medical wisdom since it’s unclear how long the immunity imparted by the vaccine lasts, particularly in older people.
Federal health officials say it’s better to get the shot whenever you can. An early flu shot is better than no flu shot at all. But the science is mixed when it comes to how long a flu shot will provide optimal protection, especially because flu season generally peaks in mid-winter or beyond.
“If you’re over 65, don’t get the flu vaccine in September. Or August. It’s a marketing scheme,” said Laura Haynes, an immunologist at the University of Connecticut Center on Aging.
That’s because a combination of factors makes it more difficult for the immune systems of people older than age 65 to respond to the vaccination in the first place. And its protective effects may wear off faster for this age group than it does for young people.
When is the best time to vaccinate? It’s a question even doctors have.
“Should I wait until October or November to vaccinate my elderly or medically frail patients?” That’s one of the queries on the website of the board that advises the Centers for Disease Control and Prevention on immunizations. The answer is that it is safe to make the shots available to all age groups when the vaccine becomes available, although it does include a caution.
The board says antibodies created by the vaccine decline in the months following vaccination “primarily affecting persons age 65 and older,” citing a study done during the 2011-2012 flu season. Still, while “delaying vaccination might permit greater immunity later in the season,” the CDC notes that “deferral could result in missed opportunities to vaccinate.”
How long will the immunity last?
“The data are very mixed,” said. John J. Treanor, a vaccine expert at the University of Rochester medical school. Some studies suggest vaccines lose some protectiveness during the course of a single flu season. Flu activity generally starts in the fall, but peaks in January or February and can run into the spring.
“So some might worry that if they got vaccinated very early and flu didn’t show up until very late, it might not work as well,” he said.
But other studies “show you still have protection from the shot you got last year” if it’s a year when the strains didn’t change, Treanor said.
So, when to go?
“The ideal time is between Halloween and Thanksgiving,” said Haynes at UConn. “If you can’t wait and the only chance is to get it in September, then go ahead and get it. It’s best to get it early rather than not at all.”