"You really should get a flu shot."
That's what top infectious disease specialist Dr. Anthony Fauci told actress Jennifer Garner during an Instagram Live on Thursday.
Fauci is strategic about getting his own flu shot. He told Garner he gets the vaccine "towards the middle and end of October."
"I wouldn't necessarily get it now, in September, because there is evidence that, in fact, the immunity might wear off when you get to February and early March...," he said, calling the advice his "unofficial" suggestion on timing.
Getting a flu vaccine is especially important this year, according to experts, because flu season will overlap with what may be a difficult fall and winter with respect to Covid-19. Given that, Fauci understands people may worry about the supply of the flu vaccines running out if they wait, but that scenario is "really unlikely," because "every year there's a certain [amount] of flu shots that we just don't use," he told Garner.
Dr. David Hirschwerk, an infectious disease specialist at Northwell Health, agrees that waning immunity after an early flu shot can be a concern. In particular, he suggests that people who are immunocompromised or elderly should wait a "little longer before getting vaccinated."
However, if you are young and healthy, "you can get the flu shot any time," Hirschwerk tells CNBC Make It.
"From year to year it can be challenging to know when exactly the influenza season begins and many experts have advised September and October are optimal times to get the flu shot," he said.