How concerned should we be about breakthrough coronavirus infections? – STAT

In the past week, you may have heard about Olympic athletes who are fully vaccinated getting positive Covid tests or people in Provincetown, Mass., or Texas Democrats or the New York Yankees. These are called breakthrough infections, and theyre causing a lot of anxiety about whether the vaccines hold up against the hyper-transmissible Delta variant.

But how concerning are they? And as cases are surging across the country, how much do they matter as a metric of the pandemic when we have a vaccine to protect against severe disease?

STAT spoke with Cline Gounder, a clinical assistant professor of medicine and infectious disease at NYUs Grossman School of Medicine, host of the EPIDEMIC podcast, member of the Biden-Harris Transition Covid-19 Advisory Board, and a member of the class of people we are calling pandemic celebrities.

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This interview has been condensed and edited for clarity.

Dr. Gounder, how concerned are you about these instances of breakthrough infections in people who are fully vaccinated?

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I think we really need to better define what we mean by breakthrough infections. Thats really a catch-all for people who might have an infection with no, or very mild, symptoms, all the way to somebody who might end up in the ICU, or even dead. What concerns me is breakthrough disease people who have significant symptoms, who are struggling to breathe, who are ending up in the hospital, and we really havent seen breakthrough disease with the vaccines.

Weve seen a lot of criticism in recent weeks about the way the CDC is handling the release of data and tracking of these breakthrough infections. Do you think their actions have been sufficient or is there more information that you think we need to have from from federal regulators?

I really think we should be tracking breakthrough infections. And heres why. Those people who are still getting infected despite being vaccinated, they may not get sick, but it is possible that they could transmit the infection on to others. And so thats something we still dont really have a handle on. There is some evidence from the sports leagues, where they do a lot of testing, that some of these people may, in fact, be contagious. And so that is concerning.

The second reason that we really want to be tracking breakthrough infections is for what we call genomic surveillance, which is where we look at new variants that are starting to emerge and what do those look like? Youre more likely to find new emerging variants among people who have breakthrough infections. Were sort of flying blind with respect to that, because were not assessing those breakthrough infections.

All this talk about breakthrough infections or breakthrough disease has also raised the issue of boosters, whether Americans will be required to go back and get reinjected with Covid vaccine. What are your thoughts on that?

First of all, booster is really not the right terminology here. I think the problem with boosters is when people hear that word, theyre like, oh, well, its going to be like a flu shot. Im going to need to get a shot every year. The way I would frame this is much more like, say, a blood pressure medicine that your doctor prescribes you where you start at one dose and they might adjust the dose over time. Just because we are still figuring out the best dosage regimen for the Covid vaccine does not mean that the vaccines dont work, and does not mean youre going to need a yearly Covid shot.

Thats really interesting. Where do you fall on the J&J vaccine and the current information we have about it? Theres so much anxiety because its just one dose. There are people who got J&J who are feeling not fully vaccinated with one shot. What do you think?

So first of all, the CDC is looking at this. In fact, the CDCs ACIP, which is a group of people who advise the CDC on their vaccination guidelines, is meeting today as we speak to evaluate whether additional doses of vaccine should be given, specifically in this case for people who have immunosuppression. But I anticipate they will be looking at other categories of patients as well.

With respect to the J&J vaccine, I think its really important for people to understand that this is a very good vaccine. This is why we thought that one dose would be sufficient. Now, what were learning is that, particularly against some of these new variants, that one dose of J&J may not be enough. And I think what you will see over the next month or two are recommendations, at least for some subsets of people who got J&J, that they do get an additional dose of vaccine. The other thing that were seeing is when you mix and match different types of vaccine, so say J&J, which is very similar to the AstraZeneca vaccine. If you mix and match that with one of the many vaccines like Pfizer or Moderna, you actually get an even better immune response. So I do think youre going to see more mixing and matching in the future as well.

So sort of a separate matter: Weve seen cases on the rise across the United States. And as you mentioned, theres this important differentiation between what might be a positive test versus what might be symptomatic disease or something more serious. And we know that vaccines are effective at limiting severe disease. But at the same time, cases are going up. How should we look at this when we have a relatively high vaccination rate and a lot of available vaccine for anyone who might want it? How should we perceive these rising case counts? How worried should we be, you know, vis-a-vis last year when there were no vaccines?

We are seeing this decoupling between cases and hospitalizations and deaths. So what we mean by decoupling is were seeing the cases shoot up more steeply than we are seeing hospitalizations and deaths shoot up. That said, it remains to be seen whether that decoupling holds because were still early in our own surge with Delta. And unfortunately, there are parts of the country that really have very low vaccination rates. And we dont know how much some of these breakthrough infections among vaccinated people might then be contributing to onward transmission and circulation of the virus among unvaccinated people. So thats really a black box at this time.

It seems like the rise in case counts has also resurrected the whole mask debate and whether we need to be wearing masks. Do we need to think about going back to wearing them?

So this is a really good question. Many local municipalities are looking at this question right now. I was on a call with several New York City public officials yesterday where they were asking for my advice on this question. I think, unfortunately, with the rise of Delta, which is about a thousand times more infectious than the original strains of the virus, we really do need to think about layering protections. And so what are those layers? Vaccination. But some of the other layers that we should consider would be masking indoors when youre outside of your household bubble, optimizing ventilation in the home just opening your window works really well. It works even better than many of those units that you can buy to filter the air. I think people really underestimate the power of opening windows. And finally, socializing outdoors as much as possible to minimize your risk. Those would be the things that I think we do need to be thinking about. At the beginning of the pandemic, the CDC said that a close contact was somebody that youre indoors with unmasked for 15 minutes or more. The equivalent of that with the Delta variant is not 15 minutes, its one second.

Does the indoor/outdoor difference in protection still hold? Lets say, somebody is worried about their unvaccinated child playing in the playground. Is it OK if theyre not wearing a mask?

The way to think about your exposure is dose times time. So your dose is a reflection of how much virus the person is carrying, but its also diluted in the air around them. So if youre indoors, theres not a lot of air dilution unless youre opening up windows and doing that sort of thing. When youre outdoors, its almost infinitely diluted. And so outdoors, your risk is really low. I think the only places that would concern me outdoors is if youre packed in together with people, say, at an outdoor concert or in an outdoor sports sporting event. But in general, outdoors is really pretty safe.

That is reassuring. How are you looking at where the pandemic goes from here? There were a lot of stories a couple of months ago thinking about how does this pandemic end. But were in a fourth surge now. And of course, many countries dont have access to the vaccine yet. How much longer is this going to go on?

Well, remember, pandemic means around the world, so across multiple continents. So if youre asking, you know, when is the pandemic going to be over? Its going to be years before this is over. I think what really worries me as somebody who, for the better part of my career, worked in HIV and tuberculosis, those are pandemics. Youre looking at about 3 million or so people dying from TB a year. A similar number of people dying from HIV per year. And thats something thats been going on for decades. And so I think this is going to become another disease of the poor and marginalized as the pandemic continues to evolve.

To listen to the full interview, check out the latest episode of The Readout LOUD podcast.

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How concerned should we be about breakthrough coronavirus infections? - STAT