The Perfect Enemy | The science and politics of COVID natural immunity - WBUR News
February 24, 2024

The science and politics of COVID natural immunity – WBUR News

The science and politics of COVID natural immunity  WBUR News

If you get COVID and recover, can that protect you from severe illness or death, even if you catch COVID again?

More and more studies say yes — that natural immunity can be just as protective as vaccination.

“There’s quite sustained — like 88% — protection at ten months after infection against severe disease and death,” Dr. Chris Murray says.

But this pandemic is all about politics, and America’s broken politics meant that public health officials sidelined the impact of natural immunity.

“If you get to the point where you don’t trust the FDA or you don’t trust the CDC in this country, we’re in trouble,” Dr. Paul Offit says.

Today, On Point: Understanding the impact of COVID and natural immunity on this country’s health, and its politics.


Dr. Chris Murray, director of the Institute for Health Metrics and Evaluation at the University of Washington. Professor and chair of Health Metrics Sciences.

Dr. Paul Offit, director of the Vaccine Education Center and professor of pediatrics at Children’s Hospital of Philadelphia. Member of the FDA’s vaccine advisory committee. (@DrPaulOffit)

Also Featured

Dr. Jeffrey Klausner, professor of medicine, infectious disease, population and public health sciences at the Keck School of Medicine of the University of Southern California. (@drklausner)

Dr. Monica Gandhi, infectious disease physician and professor of medicine at University of California- San Francisco. (@MonicaGandhi9)

Dr. Michael Mina, chief science officer at eMed, immunologist and epidemiologist. (@michaelmina_lab)


MEGHNA CHAKRABARTI: October 2020. President Donald Trump after recovering from COVID-19.

DONALD TRUMP [Tape]: I went through it. Now they say I’m immune. 

CHAKRABARTI: June 2021 American Janine Younis on CNN.

JANINE YOUNIS [Tape]: I had COVID in February, so I have natural immunity. There’s no reason for me to get the vaccine. There’s no reason for me to take the vaccine doses from vulnerable people in this country or in other countries who need more than I do.

CHAKRABARTI: September 2021 President Joe Biden. The Delta Variant Surge.

JOE BIDEN [Tape]: This is a pandemic of the unvaccinated, and it’s caused by the fact that despite America having an unprecedented and successful vaccination program, despite the fact that for almost five months free vaccines have been available in 80,000 different locations, we still have nearly 80 million Americans who failed to get the shot.

CHAKRABARTI: Also, September 2021, Kentucky Senator, Republican Rand Paul versus Health and Human Services Secretary Xavier Becerra.

RAND PAUL: You’re not willing to consider natural immunity?

XAVIER BECERRA: Senator, our team has reviewed every study that’s out there on COVID, whether it’s from Israel, from the U.S. or wherever else. They have used the facts that have been provided through the rigorous research that’s been done to reach a conclusion. 660,000 Americans or more have died because of COVID. We’re trying to do everything we can to save as many as possible. We’re using the facts. We’re following the science and following the law.

PAUL: Nobody’s arguing the severity of this, but you are completely ignoring the science of natural immunity, says Fauci. Says the whole group.

CHAKRABARTI: November 2021 CDC director Dr. Rochelle Walensky.

ROCHELLE WALENSKY: The CDC continues to recommend that people who have been previously infected get their COVID-19 vaccine. We know in our vaccine studies, our vaccine effectiveness studies with date certain when people were vaccinated, and we can prospectively follow them through our effectiveness studies and our effectiveness cohorts. The data on the infection induced immunity, some of which you quoted, are murkier.

CHAKRABARTI: This is On Point. I’m Meghna Chakrabarti. Science is an exercise in expanding human knowledge by making sense of uncertainty. American politics is an exercise in eradicating uncertainty. So in this pandemic, when absolutist politics from both Republicans and Democrats met an evolving understanding of COVID and natural immunity, what the country was left with was a hot mess of botched leadership and public health communication.

Well, there will be another pandemic in the future.

So today we want to look back at the story of COVID and natural immunity. And what the story has to tell in order for us to understand how can we do better next time? Now, our exploration is inspired by a study just published in the British journal The Lancet. It’s a meta analysis that finds that natural immunity from prior COVID infection does provide protection for at least ten months against severe disease and death from reinfection.

And that protection is equivalent or slightly better than two doses of an mRNA vaccine. Well, Dr. Chris Murray is director of the Institute for Health Metrics and Evaluation at the University of Washington. He’s also an author of the Lancet study, and he joins us from Shoreline, Washington. Dr. Murray, welcome.

CHRIS MURRAY: Happy to be here.

CHAKRABARTI: So tell us, first of all, how did you go about doing this meta-analysis about natural immunity? What does it entail?

MURRAY: We searched all the published literature for any study that was on natural immunity or immunity after infection. You know, any combination of descriptions like that. And we found all studies that had been published. We looked for studies that compared the immunity or the infection rates and the death rates and hospitalization rates in those that were infected, not vaccinated. Compared to those that were uninfected not vaccinated.

And we also looked at studies that included those who had been vaccinated and then been infected on top of vaccination and had statistically controlled for the vaccination. Put all those together and try to look at what sort of immunity as a function of time since infection that people got.

CHAKRABARTI: Okay. So then tell me, what do you think the most important aspects of the study’s findings are? I mentioned one of them, about the robust protection from natural immunity after, what, at least ten months? Tell me more.

MURRAY: So to make sense of all the noise that’s out there about, you know, vaccination and immunity after infection, you’ve got to distinguish between immunity that gives you protection from hospitalization and death. That’s the good news in this study, that at ten months you had 88% protection, versus immunity blocking you getting infected at all.

And for the latter, the immunity against being reinfected, it’s not as good. And so that tends to wane pretty quickly. And then when Omicron came along, it was much, much more reduced. But that’s true for vaccination, as well. So it’s super important to think of the two categories. Protection against severe outcomes and just can you stop transmission through, you know, immunity.

CHAKRABARTI: But as you pointed out, neither of them do that. Neither of them stop transmission.

MURRAY: Neither of them stop. I mean, they stop a little bit, but it wanes very quickly. And, you know, we have during the course of the pandemic, we’ve had to change our thinking that vaccination and natural infection is really not an infection control strategy. It’s a harm reduction strategy.

CHAKRABARTI: Well, so tell me more, or help me better understand, though, the finding that said that protection from natural immunity is equivalent or actually slightly better than two doses, specifically of the mRNA vaccine. I mean, did that part surprise you?

MURRAY: Well, not really. The fact that it was as good as or actually slightly better than vaccination is in keeping with what we would expect sort of immunologically. The surprise was the duration, that at ten months you still had 88% protection. So that’s really good news in a sense for us all.

CHAKRABARTI: Okay. And so and just remind me, how does that compare to people who maybe haven’t been infected, but have been vaccinated? Do they also have a similar length of durability?

MURRAY: They do. From what we can see on severe disease, it’s just slightly less.

CHAKRABARTI: Okay. But to your earlier point, natural immunity, though, it could provide robust protection. … You’re taking a risk, though, because you have to get infected in the first place.

MURRAY: Exactly. It’s the safest way to get immunity is, of course, through vaccination. You know, for somebody who look at what’s happened recently in China, even with Omicron, if you are uninfected, unvaccinated, the first time you get exposed, you’re at great risk, particularly if you’re over 65.

CHAKRABARTI: Okay. Now, I have to say, I’ve got foggy memory of all the things that have happened over the past three years. … Do you recall when some of the first studies about natural immunity and COVID came out?

MURRAY: You know, at IHME, we have been modeling the pandemic and, you know, at the peak of the pandemic, we were putting out new models every day and then every week. And so I tend to think of back when we needed to start to take this into account in our modeling. And that is, you know, even as early as when the new the first new variant started to show up, it became a real question mark in our minds.

And then when the studies came out in April, May of 2021, out of Israel, it became clear that post-vaccination immunity waned quickly and there were lots of studies on neutralizing antibodies, lab studies that suggested that natural immunity would also be waning at about the same rate. So we started to be pretty concerned about the speed for blocking transmission in the spring of 2021.

CHAKRABARTI: Okay. So this is really important, and I appreciate the clarification on the date. So you’re referencing again, just to remind folks this, in the spring of 2021, following the studies, for example, out of Israel, the first information about net COVID in natural immunity came out. So now I want to just get directly to the question of like, how was this evolving understanding used amongst public health and political leaders in this country at the time trying to grapple with the COVID pandemic?

So in the fall of 2021, November, specifically, then Senator Richard Burr, a Republican, questioned CDC director Dr. Rochelle Walensky about natural immunity during a Senate Health Committee hearing.

ROCHELLE WALENSKY: The CDC continues to recommend that people who have been previously infected get their COVID-19 vaccine. We know in our vaccine studies, our vaccine effectiveness studies with date certain when people were vaccinated, and we can prospectively follow them through our effectiveness studies and our effectiveness cohorts.

The data on the infection induced immunity, some of which you quoted, are murkier. They rely on retrospective studies, observational studies and studies where we can’t do a prospective study. We are following these people. We are following people who’ve been previously infected in our infection cohorts. But the data and the science are harder.

CHAKRABARTI: There’s never 100% certainty with any study. But was this a mishap, a missed opportunity by CDC Director Walensky to say, hey, potentially natural immunity is another tool in our toolkit in fighting this pandemic?

MURRAY: Well, I think it’s interesting. And, you know, at the time we thought that that position from CDC was somewhat extreme in thinking that there wasn’t protection. I think that that if you look at the contrast to what the many governments in Europe at the time were saying, there was a pretty big difference, that most of the scientists in Europe advising governments were accepting past infection as is equivalent to vaccination in terms of people being able to go out, go to restaurants, etc.

And we weren’t in this country. And I think part of it is just sort of do you take a global lens at all the data, or do you strictly look at the data sets that you particularly had at CDC is probably part of it. I also think the motivation here was probably well-meaning, that CDC was worried that talking about natural immunity would distract people from getting vaccinated. And so that sort of fed into the situation.