Dr. Nahid Bhadelia, an infectious diseases physician and medical director of the Special Pathogens Unit at Boston Medical Center, said many people often don’t realize that the flu shot doesn’t confer immediate protection, that your body needs a few weeks to build up the immunity afterward. So her advice this season is for most people to get the flu vaccine on the early side, in the coming weeks.
“Our priority should be to reduce flu activity as early as we can in communities so flu doesn’t get out of control,” Bhadelia said.
Nationally, the Centers for Disease Control and Prevention estimates the flu last season was responsible for as many 740,000 hospitalizations and 62,000 deaths. In Massachusetts, the state health department last season reported about 60,000 emergency room visits for the flu and 8,000 hospitalizations.
The Baker administration last month mandated that nearly all students under age 30 get a flu vaccine by the end of this year amid fears of concurrent outbreaks of flu and COVID-19. The administration said it has ordered an additional 300,000 doses this season and expects to have sufficient supplies to meet the increased demand.
Flu shots are offered at a variety of places, including local pharmacies and often by city and town health departments. When in doubt, call your doctor.
In New England, the yearly flu season usually begins in October and lasts through March. The results of flu tests (except for those done by rapid testing) are typically reported to the state health department, which says it has not recorded a case yet this fall. The department is slated to begin its weekly flu reporting Oct. 9
But in New York City, Dr. Peter Palese, a professor at the Icahn School of Medicine at Mount Sinai, said his hospital recorded its first case of flu on Friday.
“I don’t know the history of the patient or whether this was a traveler [who acquired the infection somewhere else], but this is a warning signal,” Palese said. “It may be we have a flu season a little earlier than usual.”
Palese noted that data from countries in the Southern Hemisphere which are emerging from winter, such as Australia, show a dramatic decrease in the number of influenza cases compared to their last winter season. He said it’s not yet clear whether something about COVID-19 knocked out or interfered with the flu virus, or whether strict measures, such as mask wearing and social distancing, prevented the flu from spreading as it normally would.
“The jury is still out,” he said.
Regardless, Palese said the best advice is for everyone over age 6 months to get a flu shot soon. The vaccine is typically found to be 40 percent to 60 percent effective in preventing illness. But even if it does not prevent a patient from getting the flu, Palese and other experts say it will decrease the severity of illness.
“We use seat belts and we insure our houses against fire,” he said. “Not every house burns down and not every car has an accident, but it is done as insurance against the actual event.”
Palese is working on a “universal” flu vaccine that, he hopes, may someday mean patients receive just one shot that will protect them for years and be more effective than the current yearly vaccine. He said a trial on a small number of patients has shown the vaccine to be safe and capable of producing an immune response, but much larger trials are needed to show if it is actually effective in protecting against the flu.
There are some concerns that — if given too early — a flu shot’s protection will wear off in older patients with less robust immune systems. But Dr. Stefan Gravenstein, director of the division of geriatrics and palliative care at Alpert Medical School of Brown University and at Lifespan Health System, said stronger vaccines typically offered to patients over age 65 provide seasonlong protection even if given in September.
“If they get the standard vaccine and not the enhanced vaccine then waning immunity has been reported by us and others,” Gravenstein said. “But in older adults this enhanced shot is paid for by insurance and they should get it.”
Another reason to get a flu shot is that it offers some protection against a heart attack, Gravenstein said. A 2018 study in the New England Journal of Medicine found hospital admissions for heart attacks to be six times higher in the week after patients were diagnosed with the flu, compared to other times.
But this flu season, that link is especially salient because both the flu and COVID-19 prompt an inflammatory response in patients. And people with underlying health conditions, such as coronary artery disease, are already at increased risk of severe illness from COVID-19, according to the CDC.
“When people get infected, whether it’s influenza or a bladder infection, it produces an inflammatory response, and that inflammatory response as the body tries to fight the infection increases the ability of the blood to clot, and when it clots it plugs, and when it plugs capillaries in the heart, you get heart attacks,” Gravenstein said.
Still, some patients are reluctant or fearful to get a flu shot. Gravenstein said this year, especially, is not the time to hesitate.
“When I have patients who are reluctant to get the vaccine, many have quit smoking, and I say to them, that was hard,” he said. “But how hard is this?”