For anyone debating whether to get a flu shot this season, North Suffolk emergency medicine physician Keith Batts has one piece of advice.

“Everybody should,” he said Thursday at Bon Secours Health Center at Harbour View. “It’s the people that don’t get flu shots that are helping to transmit (flu) from person to person.”

While low-cost flu shots are available at pharmacies and medical offices, Bon Secours will have them for free at the health center, 5818 Harbour View Blvd., on Sept. 27.

Adults, children and infants can drive onto the parking lot, roll down their window and receive a free shot from a registered medical practitioner. It’s taking place while supplies last — health system spokeswoman Kasey Fuqua said 500 shots would be available from 8 a.m., and the operation will conclude no later than 11 a.m.

With temperatures in the 90s this past week, it might seem too early to be worrying about the flu. That’s just wrong, according to Batts.

“It’s not all that early,” he said. “The peak is usually the January and February timeframe, but it can come as early as October.”

A flu shot at the end of September is “actually pretty perfect timing,” he said.

It’s impossible to predict ahead of time what a given flu season will be like, says Laurie Forlano, an epidemiologist with the Virginia Department of Health.

“Flu viruses change every year, and it’s not completely unusual for a new one to occur every year,” Forlano said.

The phrase “herd immunity,” often heard in association with the seasonal flu, refers to a community’s level of immunity, she said.

“When a larger proportion of a community is immunized, that affords protection to the group.”

But folks shouldn’t not get a flu shot because they think most other people will get one and create herd immunity, according to Forlano. “It is still very prudent and recommended and wise to get your own vaccination, especially if you are more vulnerable,” she said.

More vulnerable are the very young — babies especially — people with underlying health conditions and older adults who may have chronic illnesses, she said.

The flu vaccine covers the three main strains experienced in the U.S. in the past several years, Batts said.

Everyone over 6 months old should be vaccinated every year, he said. He also pointed to the area’s high concentration of military families.

“It’s a transient-type community, so we are getting travelers from out of the country,” Batts said.