Dr. Helen Chu

Thanks for having us.

We think of vaccines as preventing the disease that we're vaccinating against, flu or RSV or COVID.

But oftentimes, these vaccines can have other effects, like preventing heart attacks or strokes.

There are a couple of reasons why we think this happens.

The first is perhaps we are not measuring the infections when they occur.

So very well may be that somebody comes in with a heart attack, and the trigger for that heart attack was a flu infection, but we never captured that flu infection.

And so when we look at this on a population level in studies, what we can see is that flu vaccines actually prevent heart attacks.

That's correct.

It could be preventing that.

And it's possible that the flu infection is triggering inflammation in your blood vessels.

And that inflammation is what's causing the heart attack or the stroke.

We think that's what's happening.

And we're not able to measure that in the way we normally do these studies.

I think the main point is that either we're not measuring it or these things are happening well after the infection is being diagnosed.

And so it could be that you could have a heart attack at the time of your hospitalization for flu, but we never captured that flu infection.

The other way that it could happen is that that heart attack or stroke happened a few weeks to months later.

And we're not capturing it because it wasn't at the time of the immediate infection, but that infection triggered this cascade of inflammation that later on led to all of these other adverse events like strokes or heart attacks.

I mean, I think this is all very interesting and really exciting to see this.

And they're called ecologic studies, where you look at the before and after and compare these groups.

I think that we do need to see some more data.