The science and politics of the new mRNA flu vaccine

Flora Lichtman (0:02)

Hey, it's Flora, and you're listening to Science Friday.

A new mRNA flu vaccine made by Moderna was approved by the FDA in August. It's currently available for people age 50 and over. That was the age group studied in the clinical trial. Now the promise of an mRNA flu vaccine is that it could be spun up quicker than a traditional vaccine, meaning in theory, you could get a better match to the year's flu strain that's circulating.

Is that what happened this year? How are the side effects going? And how has dysfunction at the health agencies impacted the rollout? Those are some of the questions we're going to tackle today with Dr. Anna Durbin, vaccine researcher and director of the Center for Immunization Research at the Johns Hopkins Bloomberg School of Public Health. Anna, welcome to Science Friday.

Anna Durbin (0:50)

Great. Thank you so much for having me, Flora.

Flora Lichtman (0:53)

Thank you for being here. Is this year's mRNA vaccine a better match with the circulating strain of flu?

Anna Durbin (1:00)

This mRNA vaccine contains the exact same strains as the inactivated and other vaccines that are being used this season. The reason for that is our current method of choosing which flu strains go into the vaccine is based on a meeting that we have twice a year. Once is to pick the Northern Hemisphere strains. That meeting occurred in March.

The second meeting just occurred last week, and that's to pick the strains for the Southern Hemisphere.

But it's October, so the strains that we picked in March, we're hoping will be a good match for what's circulating in the fall. But the biggest issue we have right now is because of the amount of time it takes to make our traditional flu vaccines, we need a long lead time in strain selection. That's why we think that there's great promise with mRNA vaccine that we can make those vaccines so much more quickly. But it's just not the ability to make the vaccine. We have to have FDA regulatory guidance on which strains to include in that vaccine. As I said, that meeting occurred in March of 2026

Flora Lichtman (2:13)

Is that an FDA meeting or a WHO meeting?

Anna Durbin (2:15)

There's two. There's a WHO meeting which picks the strains globally, and then there is an FDA meeting which specifically picks the strains for the vaccines that are being used in the US.

Flora Lichtman (2:27)

So why didn't we have an FDA meeting after March?

Anna Durbin (2:30)

That is a great question. I will say at the meeting in March, several members of the committee suggested that very thing. What the members of the committee said is, this is an mRNA technology. We can make the vaccines faster. Why don't we have meetings more frequently? The FDA has heard this on a couple of occasions. I think the agency is looking at that, they're evaluating that, and they're trying to determine whether or not that will happen.

I'm very curious and interested to see if we will have a meeting over the summer for the Northern Hemisphere, as opposed to just in March. I think the jury is out on that. We don't have a firm answer yet, but we're encouraged that the agency is considering it.

Flora Lichtman (3:17)

It doesn't seem that hard to hold a meeting.

Anna Durbin (3:20)

It doesn't, but there is bureaucracy, and with the current administration in the FDA and just in HHS, whether or not that's going to happen, I think, as yet to be seen.

Flora Lichtman (3:35)

So this is the first year that this mRNA flu vaccine is available. Is it being evaluated in some way and how?

Anna Durbin (3:42)

So every year, CDC, as well as other groups, influenza surveillance systems occur throughout, not just in the United States, but globally. So there's different groups out there that evaluate, one, what is the flu activity? What strains are happening? How is the vaccine coverage and how is the vaccine affectedness during that season? So that will occur this season just as it occurs every season.

I think one of the great problems that we have right now is the reduction in workforce that we saw at CDC and FDA and at IH, frankly, about a year ago. And that, having to do more with fewer people is difficult. But we will look at overall, what was the match between the strains and influenza. I think what I'm really interested to see in this coming influenza season is whether we will get some indication of effectiveness of the mRNA vaccine compared with the historical standard vaccines that we have.

Flora Lichtman (4:47)