A New COVID Wave Is Here, Raising The Risk Of Reinfections

IRA FLATOW: This is Science Friday. I’m Ira Flatow. I’m really eager to do this update on COVID for many reasons, but mostly because COVID is surging in the US again, and it’s raising so many questions. The latest subvariants BA.4 and BA.5 are now dominant, and things are feeling a little different during this surge, don’t you think?

I mean, people who recently got COVID are getting reinfected. The variants appear to be really contagious, and those who have so far evaded the virus are getting it for the first time. What about the boosters? How much should we rely on a new booster slated to roll out in the fall to boost our immunity against the virus?

Dr. Anthony Fauci says don’t wait for the new ones this fall. Get vaccinated now. But will they be ready for when my booster runs out in October? And masks. Should we all be masking up again indoors? Joining me to help us debunk the latest COVID misinformation and update us on the current state of COVID are my guests, Katelyn Jetelina, adjunct professor at UTHealth School of Public Health and author of “Your Local Epidemiologist Newsletter.”

She’s based in San Diego, California, and Jessica Malaty Rivera, epidemiology fellow at Boston Children’s Hospital, senior advisor at the Pandemic Prevention Institute based in San Francisco. Jessica, welcome to Science Friday. Dr. Jetelina, welcome back.

JESSICA MALATY RIVERA: Thanks for having me.

KATELYN JETELINA: Yeah, thanks for having me.

IRA FLATOW: Jessica, let me begin with you. Break it down for me. How big a difference is there between these new variants and the original Omicron variant?

JESSICA MALATY RIVERA: There is a pretty noticeable difference. When we talk about the technicalities of where these mutations are in the spike protein, it has proven to be different enough where previous infection is not something that we can really rely on for protection of a new infection. And it is something that is a little bit confounding in the sense that we thought it would be a little bit more linear in the way that the virus is evolving and it’s having a lot of offshoots. And because of that, it is complicating things.

It is making it so that a lot of things we previously assumed on the window of time you had before you could get reinfected was longer, it’s probably not that anymore, because it is different enough. Now, it is still sars-cov-2. I don’t want folks to think that it is completely different. It is not some scary Frankenstein version of the virus, but it is definitely evolved to a place where we are now talking about more variant-specific immunizations to protect us.

IRA FLATOW: And more people, Katelyn, are getting reinfected. Why is that?

KATELYN JETELINA: Yeah, that’s right. So it looks like about 25% of new cases right now are reinfections. This virus is mutating to really skirt around our first line of defense, which is called neutralizing antibodies. Omicron keeps mutating to do this better and better and then there’s also the combination of antibodies waning over time, so this wall of defense is just getting shorter and shorter with time, and that’s expected. And then third, some people just don’t mount an immune response after a primary and typically mild infection.

And so unfortunately with more transmission, this rapidly evolving virus and a virus that did recently mutate to become less severe than Delta, we can expect and should expect sars-cov-2 reinfections.

IRA FLATOW: That’s good that you’re bringing that up, because we used to think about 90 days as the benchmark of when you can’t get reinfected. But that window is a lot shorter now, right?

JESSICA MALATY RIVERA: It is. And it’s not something that I think folks should really take as infallible or that it is absolute, right? So it has always been variable. It has been roughly 90 days in the past, but now, as Katelyn mentioned too, because of this immune evasion that we’re seeing, because of all these different variables that have affected how this virus is now transmitting in the community, it’s sometimes 30 days. It’s sometimes 60 days and sometimes it’s even less than 30 days for some unlucky folks.

IRA FLATOW: So if they get reinfected, are you more or less likely to have a severe infection the second time around?

KATELYN JETELINA: You’re less likely to have a severe infection. We’ve seen many studies that show 60% to 90% lower odds of resulting in hospitalization and death with a reinfection compared to a primary infection. But that’s not 100%. There are definitely still people that can have a severe reinfection. We are seeing that, especially if you’re unvaccinated, if you’re older, if you have comorbidities, and so that’s why I– as an epidemiologist, it’s really important to me that we continue to keep transmission down and we continue to have many layers of protect so we can try and avoid reinfections as much as possible.

IRA FLATOW: Yeah, because there are some people that say, OK, I want to jump in the pool and get infected already, right? Get it out of the way, because I’m going to get it. That’s not a good idea.

JESSICA MALATY RIVERA: It’s not. No, getting an infectious disease is not an infectious disease strategy or a public health strategy for that matter. And I think that it’s because there were some very poor comparisons in the earlier days of the pandemic that once you got it you could be protected. Once you got it plus being vaccinated you were ultra protected. And again, because of this dynamic of the virus evolving so much and so rapidly, it’s not a good strategy. Not to mention the fact that there is a very real risk of long COVID and so many unknowns related to long COVID that it’s not really the gamble that you want to make.

IRA FLATOW: I’m glad you brought that up, because there’s a lot of confusion circulating about that and about how long you remain contagious with COVID and how to find out whether you can spread it or not. I mean, we are told to keep testing at home, but some of us are getting the PCR test at a clinic because our doctor tells us to. Jessica, are they both good and equal indicators of our risk?

JESSICA MALATY RIVERA: They’re both really effective tools, but they do different things. And I think right now, and I’m a bit surprised two plus years into the pandemic where I’m still seeing even coming from some medical professionals confusion about how to use the PCR test and when to use a PCR test and when not to compare it to antigen testing. We know that PCR tests are incredibly sensitive and specific, and they are excellent tools for determining detectable virus in your body. But if you are recovered, it’s very likely that you could be testing positive on PCR for several weeks, even a couple of months because it is so sensitive it’s detecting even those fragments of the genetic material of sars-cov-2.

On the flip side, antigen tests are not a perfect proxy for determining infectiousness, but they are a really good indicator of active infection. You’ve probably seen folks on Twitter talking about if you have a really dark second line on your antigen test, odds are you have a lot of virus and you should be isolating in that time. Antigen tests are very specific, and they are going to detect active virus. They’re going to detect the spike protein on the virus.

And so to me, I think that if you’re still testing positive on antigen test, not PCR, it’s a good sign that you should still be in isolation and keeping away from others.

IRA FLATOW: And Dr. Jetelina, do you agree? Should people be testing before determining if they should leave quarantine?

KATELYN JETELINA: Absolutely. And at-home antigen testing is one of the best tools we have right now to break transmission chains. I think that there’s a little difficulty with antigen tests specifically at the front end of infection. This is when we see false negatives more common, especially with Omicron. And so when we’re surging like we are right now, if someone has any symptoms, I just wouldn’t trust a negative test right now.

I would always assume that you have COVID 19 and to retest in about 24 to 48 hours, because it will likely turn positive. Now, antigen tests are really good at telling us when we’re not infectious anymore because we have very few false positives. So if you find a positive and then you get a negative after that, I would trust that a lot and trust it to leave isolation only once that antigen test is negative. We see pretty strong evidence that an Omicron infection lasts, on average, about 8 to 10 days.

Now, some people will be infectious for less, some will be infectious for more, and you really won’t know unless you test.

IRA FLATOW: That’s interesting because the CDCs current quarantine guidelines are to isolate for five days after the onset of symptoms then wear a mask around other people for five days. You’re saying that’s not enough?

JESSICA MALATY RIVERA: It’s not enough, and I think Katelyn and I have both gone on the record very publicly to talk about how misguided that recommendation is, mostly because we know that it was actually based on Delta data and not Omicron, which is when they actually issued it. I have yet to meet a person who is asymptomatic and negative within five days in an Omicron infection. It’s allergy season, there’s other colds. People are getting confused about those negative tests early on, but they may actually be positive, and so these false negatives are a big concern if people are just counting down this rigid day of, oh, I only need to stay home for five days and then I can just wear a mask.

If you have any symptoms and if you are testing positive, that is a really good sign that you are infectious and that you should be staying home until you test negative and until you are asymptomatic. I think there was a lot of confusion too about is it asymptomatic, is it resolving symptoms? To ask people to interpret resolving is very, very difficult. And I think that opens a huge can of worms and causes way too much gray for people to be making decisions on something like infectiousness.

IRA FLATOW: So keep testing is what you’re saying?

JESSICA MALATY RIVERA: Definitely keep testing.

KATELYN JETELINA: And I will say, Ira. I agree with Jessica, I do not like that CDC guidance at all, but because that CDC guidance is there, some people just can’t stay in isolation that long because they need to go to work or their employers won’t allow them a longer isolation because that’s what the CDC says. And so if someone does have to leave isolation after five days and they’re still testing positive, which there’s a really good chance that there is, they really need to wear a good mask, one that’s well fit, one that’s filtered, and everywhere once they leave isolation until they test negative again.

IRA FLATOW: I’m glad you brought that up. It’s a good segue to talk about masking up, because I see that people are not masking up, and I see the new recommendations coming out that we should be masking up in closed places indoors with other people. Do you agree, Jessica?

JESSICA MALATY RIVERA: I do. I mean, I always caveat my recommendations on these personal mitigation efforts with the fact that my risk tolerance is very, very low and is probably lower than the average person. I have young children at home. I don’t want to get COVID. That said, I still think that wearing a mask is a very simple task, and at this point with high transmission, it seems like a really good practice for folks to be wearing high quality masks when indoors, when in large gatherings.

I think these variants BA.4 and BA.5 have also shown us that outdoor transmission is possible. Outdoor transmission has always been possible, it’s just a little bit more possible now. Now, obviously, things outdoors are safer and I’m still doing things outdoors even unmasked depending on the crowds, but I think masking in high risk settings especially indoors in traveling when you’re around folks who are immunocompromised or high risk or if you’ve yourself done something very high risk or you feel a tickle in your throat. Wearing a mask is a responsible thing to do.

IRA FLATOW: Yeah. Yeah, I’m getting looked at, but I don’t care when I have my mask on. Katelyn, we talked about how BA.5 is better at circumventing our immunity, either from prior infection or from vaccines. And this week the Biden administration announced that they are planning to ask for approval for people under 50 to be able to get a second booster. Would that do anything to blunt the current wave?

KATELYN JETELINA: So boosters, especially very recently they do prevent infection. I think there’s a lot of misinformation that they don’t, and the reason that boosters do that is because they really ramp up neutralizing antibodies. Unfortunately, like I said before, these antibodies wane, but those neutralizing antibodies are effective in reducing infection. And if you don’t get infected, then you can’t transmit it. I think it’s also really important, though, that we start walking away that the purpose of vaccines is not to prevent infection.

The purpose of vaccines is to prevent severe disease and death. And what we’re seeing with a second booster, especially among adults over age 50 is that it broadens protection. That those people with two booster doses have about four times lower risk of dying from COVID-19 compared to those that just received one booster dose. Certainly, if you’re over the age of 50, go get your second booster now. Don’t delay.

Don’t wait for that Omicron booster. Also, if you’re under 50 and have multiple comorbidities or even work at a high exposure occupation, I think it makes a lot of sense to get that second booster now.

IRA FLATOW: So when you say don’t wait for that Omicron booster coming out in the fall, what about people whose boosters are running out by the fall? It’ll be six months– four, five, six months by the time that booster comes around.

JESSICA MALATY RIVERA: The number of people who have even received their booster is not very high, which is a bit discouraging. We have less than 50% of the eligible population in the US that has received a booster dose. So it’s certainly not harmful for folks to get a second booster if it becomes available. My concern is it’s similar to what Katelyn said, we have this tendency to look at vaccines as a silver bullet. That it somehow trumps all the other mitigation, but mitigation has to be layered.

It has to be all the things we’re talking about, masking, distancing, isolation, testing. We can create this false expectation that these next boosters are going to somehow be even more comprehensive than they are, but really, what it’s going to do is just buy a little bit more time from maybe an infection or severe illness, but it’s really not going to necessarily stop the pandemic.

IRA FLATOW: This is Science Friday from WNYC Studios. Speaking of new boosters, could we see an entirely new variant, like the original Omicron, that comes from an entirely different lineage and therefore this booster won’t really help?

KATELYN JETELINA: So there is the possibility of an Omicron-like event. A variant coming out of the blue that really changes the game. The last estimate I saw was that we have about a 30% chance of that happening within the year, so it’s not zero, but it’s not 100% chance. We expect and hypothesize that Omicron will continue to mutate into these ladder-like mutations.

And so I expect that even once we have this Omicron booster rollout in October, there’s already going to be a new Omicron variant taking hold, but that’s OK. The purpose of boosters and variant-specific boosters is not to chase the variant. We’re never going to win that rat race. The purpose of it is to broaden our protection, and no matter what Omicron variant is circulating, an Omicron-specific booster this fall will no doubt help against that.

IRA FLATOW: Do you expect that all of us sooner or later are going to get infected?

JESSICA MALATY RIVERA: Personally, I do.

KATELYN JETELINA: Yeah, I remember back in March of 2020, Fauci said that he expects by the time this is done 80% of people will get infected. At the time, I didn’t believe it, but now, absolutely. I think that it’s going to become part of our lives. We have to put sars-cov-2 in this repertoire of what we encounter if we want to balance that with our quality of life, and I think it’s going to happen.

All we can try and do is to reduce that viral load as much as possible by using a lot of these layers and mitigation. So hopefully, we help our immune system along the way to fight it as quickly as possible.

IRA FLATOW: Well, both of you have certainly helped answer my questions and I hope our listeners questions to this has been very, very enlightening, and thank you both for taking time to be with us today.

JESSICA MALATY RIVERA: Thank you so much.

KATELYN JETELINA: Yeah, thanks for having me.

IRA FLATOW: Dr. Katelyn Jetelina, adjunct professor at UTHealth School of Public Health and author of “Your Local Epidemiologists Newsletter” based in San Diego, and Jessica Malaty Rivera, epidemiology fellow at Boston Children’s Hospital, senior advisor at the Pandemic Prevention Institute based in San Francisco, California.

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