Health officials argue the protection of the COVID vaccine booster wanes over time and say some people need a second booster. But other infectious disease experts say three shots are enough for now.



The Biden administration authorized a second COVID booster for people age 50 and older and those who are immunocompromised. So if you are eligible, should you get a booster? NPR health correspondent Maria Godoy is here to help us think that through. Good morning.

MARIA GODOY, BYLINE: Good morning, Steve.

INSKEEP: Let's start with the officials. Why do federal health authorities think this is the time?

GODOY: Well, the COVID vaccine booster shots have proven highly effective at preventing severe disease and death. But immunity does wane over time.


GODOY: And federal health officials are concerned about people considered to be at highest risk of getting severe COVID. That includes people 12 and up with weakened immune systems. It also includes people starting at age 50. Officials are recommending a second booster for both these groups if they had their first booster at least four months ago.

INSKEEP: Thanks for that last detail. So I should be thinking about when did I get a booster, how long ago, and trying to remember that. So older people are at risk. But why would the dividing line be 50 years old?

GODOY: Well, here's Dr. Peter Marks of the FDA.

PETER MARKS: We know that people in the age range from about 50 to 65 - about a third of them have significant medical comorbidities.

GODOY: And by comorbidities, he means conditions like obesity, lung disease, diabetes, which is fairly common in this age group. These can raise the risk of getting seriously ill from COVID or even dying.

INSKEEP: Well, this might make me think then. Suppose I'm over 50, but I feel like I'm very healthy. I don't have any of those comorbidities. What should I do?

GODOY: Well, several experts NPR spoke with say if you're in your 50s and healthy, there's really no need to run out and get a second booster. Dr. Peter Chin-Hong is an infectious disease specialist at UCSF, and he pointed to a study from Israel that found people age 60 and up who got a second booster had a lower risk of severe outcomes and dying than those who only got one booster. But he says the bottom line is having any booster was really protective.

PETER CHIN-HONG: Whether or not you got three shots or four shots, the survival rate was really high. So where does that leave us? It leaves us in a situation where you probably should walk to go to get the second booster if you're eligible - probably walk a little faster the older you are.

GODOY: So the older you are, the bigger the benefit of a second booster. But he says getting that first booster shot is the most important.

INSKEEP: I'm just enjoying the image of people regulating their walking or running speed, depending on their exact condition.

GODOY: It's very vivid.

INSKEEP: So should I walk or run if I've previously had COVID?

GODOY: You know, I asked that of Dr. Preeti Malani. She's an infectious disease doctor and geriatrician at the University of Michigan, and she notes that a lot of Americans got infected during the omicron surge.

PREETI MALANI: There's a thought that - especially individuals who had COVID and are also vaccinated and boosted - that they probably get a free pass for at least a few months. And in those cases, you may want to wait.

GODOY: There's really good evidence that a recent infection essentially acts like another shot to rev up your immune system. So you have a few months before you need to think about getting another booster.

INSKEEP: When you pull all this together, is there an optimal time then to get a second booster?

GODOY: Yeah. Ideally, you'd want to pump up your immune system right before another surge, but it's unclear when that will happen. And if you do it too soon, that extra protection will eventually wear off. As one expert said, it's a little bit like trying to time the stock market.

INSKEEP: Better to just put your money in a mutual fund, I suppose.

GODOY: (Laughter).

INSKEEP: Maria, thanks so much. Always a pleasure.

GODOY: My pleasure.

INSKEEP: NPR's Maria Godoy. Transcript provided by NPR, Copyright NPR.