Is it possible to get the flu vaccine too early?

It’s time to start lining up for flu shots already, according to the Centers for Disease Control and Prevention. But when is the best time to get that vaccine?

The CDC advises all adults and children (older than 6 months) should get a flu vaccine by the end of October. Getting vaccinated before flu season strikes may well offer the best protection, the CDC says. Yet not everyone agrees that’s the best plan, especially for senior citizens.

The timing of the shot is not a cut-and-dried issue. There are those who worry about getting the shot too early so that their immunity wears off long before the gnarly flu months of January and February hit in full force. Some studies suggest vaccines lose protectiveness during the course of a single flu season. In people over 65, NPR reports, the protective effect may wear off faster than it does in young people. Seniors may want to mull it over before they do the early bird thing.

“The data are very mixed,” Dr. John J. Treanor, an infectious disease specialist at the University of Rochester medical school, tells NPR. “So some might worry that if you got vaccinated very early and flu didn’t show up until very late, it might not work as well.”

But other studies show “you still have protection from the shot you got last year,” Treanor adds, “if it’s a year when the strains didn’t change.”

It should be noted that the flu shot is far from perfect. Last year, it was only about 36 percent effective. However, the shot, which has been tweaked in the hopes of targeting current strains of the virus, is usually more effective in children. The good news is that both standard vaccines and nasal sprays are recommended for the 2018-2019 flu season.

The CDC notes that “delaying vaccination might permit greater immunity later in the season,” but it says that “deferral could result in missed opportunities to vaccinate.”

The vaccine reminder comes after last year’s particularly intense flu season, which according to the Academy of Pediatrics was the third most severe since 2003-2004 and the first to be classified as high severity for all age groups.

More than 700,000 people were hospitalized with the flu during last season and about 180 children died, CNBC notes. About 80 percent of the children who died from the flu last season weren’t vaccinated.

There’s no way to predict what this year’s flu season will be like, but the usual precautions should be taken. In addition to getting the shot, wash your hands, cover your cough and stay home from school or work if you do get sick. Stocking up on cough drops and tissue won’t hurt either.