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Brian Lehrer: Brian Lehrer on WNYC. With me now, WNYC health and science editor Nsikan Akpan. He's got an article on Gothamist now called Why the Delta Variant Matters if You're Vaccinated or Unvaccinated. Hi, Nsikan. Thanks for coming back on the show.

Nsikan Akpan: Hey. How's it going? Anytime.

Brian Lehrer: As an example of how much more transmissible the Delta variant is than earlier ones, you say the simulation that somebody did about what we might expect to see in the Bronx, where only about 40% of adults are vaccinated, the lowest rate among the five boroughs. Can you describe that simulation? Who did it and what it seems to predict?

Nsikan Akpan: That's right. Everyone has been saying that the Delta variant spreads faster than its predecessors. I really wanted to show just what that could mean for an unvaccinated population or one that's had about 40% vaccination. I reached out to PHICOR a public health research lab at the City University of New York to build a simple outbreak model for the Bronx. The simulation basically shows how many people might be susceptible, exposed, infected, or recovered each day during an outbreak. Based on early studies, the Delta variant spreads about twice as fast as the original strain of the coronavirus.

Alpha or the UK variant spreads about 50% faster than the original. If you take 10 people and they have each of those viruses and you drop them into a completely unvaccinated Bronx, the Delta variant would create an outbreak that peaks with about 67,000 cases after about 2 months. The Alpha variant or the UK variant would peak with 47,000 cases after 3 months. The original strain of the coronavirus would peak with about 26,000 cases after 4.5 months. The Delta variant hits harder and faster in that unvaccinated scenario.

A similar pattern would also emerge at the Bronx's current rate of vaccination around 40%, but that outbreak would be less intense. Delta's peak would be about 28,000 after 3 months, Alpha would be about half that at 17,000 cases after 4.5 months, and the original strain would barely register. The takeaway is really that the Delta variant causes way more damage simply by being able to spread faster in a community.

Brian Lehrer: Hello, Bronx, get vaccinated.

Nsikan Akpan: Bronx, Brooklyn, Upper Manhattan, most of the Staten Island, I think any place where the vaccination coverage has really fallen behind, you want to get vaccinated. I think one way to look at it is Missouri. We've been talking about Missouri a lot this past week because they're facing a surge of the Delta variant, and they're about 40% vaccinated. The Bronx is about 40% vaccinated, but you have to think of the Bronx, the population density, you just know how many more people are mixing in that Borough, it's much higher than Missouri. If Delta catches hold there or really in any dense urban neighborhood that's unvaccinated, it could be really problematic.

Brian Lehrer: I knew the Bronx must have something in common with the state that elected Josh Hawley to the senate. It's just too bad that it's this. Your article cites a study from the UK that indicates that people are not well protected from the Delta variant with one shot of the Pfizer vaccine. Of course, the Pfizer vaccine is supposed to be a two-dose regimen to begin with. What does that study really tell us? Why did those British scientists even test it that way?

Nsikan Akpan: They looked at one or two doses of Pfizer and one or two doses of AstraZeneca. The reason that they do that is mainly because it's easy and they can. Everyone will have time between their first and second dose. If a person catches the virus during that in-between period, you can measure the effectiveness after one dose. I can also give us a sense of what partial immunity looks like. That can be a proxy for people who previously caught the virus, but haven't been vaccinated.

Brian Lehrer: We should say those studies found two shots of the Pfizer were 96% effective against getting COVID bad enough to be hospitalized. Are the Pfizer and Moderna vaccines about as effective against the Delta variant as against previous ones?

Nsikan Akpan: Absolutely. I think the big takeaway, and there's a lot of news swirling around this right now. The main takeaway from the British studies and also from what we're seeing in countries like Israel is that two doses of the COVID-19 vaccine, namely Pfizer and AstraZeneca, will still protect against the overwhelming majority of cases that are symptomatic and ones that lead to hospitalization when it comes to the Delta variant. We have less data on the Moderna vaccine, but an analysis that they put out earlier this week shows that, yes, the Moderna vaccine should be able to neutralize the Delta variant. It is looking good. If you take two doses of those vaccines, you should still be protected, even if you experience a breakthrough infection.

Brian Lehrer: How about the Johnson & Johnson?

Nsikan Akpan: J&J hasn't released much data on its vaccine and its variants. When I wrote this story there was essentially only one study showing that its vaccine could neutralize the Beta and Gamma variants. Those are the ones that originated in South Africa and Brazil. We actually have some fresh data right off the presses. A South African study, that's following 400,000 healthcare workers who took the Johnson & Johnson vaccine, that was primarily the vaccine that was being used there until recently. That study shows very few breakthrough infections result in severe cases in that group of people.

It didn't say how many breakthrough infections occurred overall. A publication is expected in the next few days or in the next week, but they are finding that 94% of breakthrough infections are mild, 4% are moderate, and only 2% are severe.

Brian Lehrer: That's good news. You're right that researchers say the real implication of the one dose study, one dose of Pfizer instead of two, is that one dose recipients offer a preview of what happens to people who live on the margins of solid immunity. Who do those people tend to be? What does that term mean, on the margins of solid immunity?

Nsikan Akpan: For as long as COVID-19 is around, the calculus will always be slightly different for people who would be at very high risk for severe disease if they weren't vaccinated. With the vaccines, we know that weaker immune systems become stout, they become stronger, and that sturdy immune systems, they become ironclad, very unlikely that somebody will suffer a severe case or death if you have a sturdy immune system. The people who are on the margins of solid immunity, that'd be senior citizens. We know that our immune systems weaken as we age, immunosuppressed individuals and people with certain underlying medical conditions where we know that it harms, it weakens the immune system.

Brian Lehrer: Now, this is where it gets a little scary for vaccinated people and people get confused about whether to be more afraid or more reassured by the results that we're seeing around the world. I don't want to cause any undue alarm. Emphasize what you have just said already in this conversation about how the vaccines at full doses tend to prevent against severe cases in the vast majority of people. Your article notes that in Israel, where more than 80% of adults are vaccinated with Pfizer vaccine, half the new Delta Variant cases recently have been in vaccinated people, according to Wall Street Journal article.

In the UK, studies find the Pfizer vaccine 96% effective against hospitalization level COVID really, really good, but still, deaths are rising in the UK among fully vaccinated seniors. It looks like they define that as people over 50. Do we conclude that getting hospitalized or dying from the Delta variant is still very, very rare if you're vaccinated, but vaccinated senior citizens are a little more at risk than from previous variants?

Nsikan Akpan: Yes. I think that's the conclusion. I think Delta changes what we can expect slightly for people who are older. I think to put everything in context with the numbers that we're getting from Israel. If you say half of these new cases are people who are vaccinated, you have to think that-- Actually, we do expect some number of breakthrough infections and you should really be looking at those breakthrough infections in the context of how many millions of people were vaccinated overall.

I think when you do that, you see that the breakthrough infection rate is actually pretty, pretty low, and probably around what we would expect. I think for the UK data, they're seeing more deaths in people who were vaccinated versus unvaccinated, but there are a couple of things to consider there. One, they've only recorded about, I think it's like 117 deaths. [crosstalk]

Brian Lehrer: Let me just jump in.

Nsikan Akpan: I'm sorry. Go ahead. Sure, sure. Yes.

Brian Lehrer: I think you might have misspoke there for one second. You didn't mean to say that they're seeing in the UK more deaths among the vaccinated than the unvaccinated.

Nsikan Akpan: I meant only for people who are over 50. They are seeing slightly more deaths among the vaccinated than the unvaccinated people who are over 50. Yes, exactly. The context for that is that they've only recorded about 117 deaths so far. That's a really, really low number. I think the Delta variant is still gaining steam in the UK, and we know that, looking at the latest numbers over the past few weeks, that the majority of the infections have been in people who are unvaccinated.

I wouldn't be too surprised to see that death toll, those numbers flip going forward as it makes its way through the population because right now, a lot of the cases, the majority of the cases are in young people, but we know that whenever COVID-19 surges, it starts in young people and then it finds its way into older populations. The other caveat where we really need to consider with that death data point is that I think it's greater than 80% of the people who are over the age of 50 in the UK are vaccinated.

If you're going to have a case or a death in somebody in that older age group, it is more likely to be in somebody who is vaccinated. There could be a skewing there because almost everybody who is over 50 is vaccinated. If there's a breakthrough infection it's going to happen to somebody [crosstalk]--

Brian Lehrer: If the more serious cases tend to happen in older people, and the older people are generally vaccinated, then it's going to follow that the more serious cases by the sheer raw numbers are more in vaccinated people, even though that winds up being a little misleading. Listeners, we can take a few phone calls for our health and science editor, Nsikan Akpan, whose new article on Gothamist is called, Why the Delta Variant Matters if You're Vaccinated or Unvaccinated. 646-435-7280. 646-435-7280, or tweet your question @BrianLehrer.

To continue what we were just talking about, this suggests the question of how cautious even healthy seniors should be in reopening their lives, seniors plus people who are immunocompromised or have other serious underlying conditions that make them vulnerable to COVID. In fact, the US Centers for Disease Control and the World Health Organization seem to disagree right now over how cautious people need to be. The WHO says vaccinated people should still wear masks indoors and avoid crowds, for example. The CDC is not going that far. Is it possible to say if that difference is more based on politics or different interpretations of the science?

Nsikan Akpan: I think from our experience in the United States people have been extremely reluctant to wear masks. I think some of the barrel burning ceremonies that we saw where people were checking masks into barrels and burning them, I think shows you that the animosity against wearing masks. I wonder if the policy here in the United States might change. This is a rapidly evolving situation. Personally, I'm fully vaccinated and I'm going to start wearing masks indoors again just because I think we need to see exactly what's happening with the Delta variant.

When we're in these moments where there's uncertainty, a little bit of extra caution when it comes to just wearing a mask indoors, you can still take it off the outdoors. We know that the outdoors is very safe, but just wearing a mask indoors, if that's the only extra step that I have to take, then it's probably going to be the one that I'm going to take until we know for sure what the risk is with the Delta variants.

Brian Lehrer: Indoors with mixed households, I guess. Do you know if the WHO advice for vaccinated people to avoid crowds even pertains to crowds outdoors? You just repeated what I think everybody says, who's in the know about this at this point? Being outdoors is overwhelmingly protected, but it wasn't clear to me from what I read, if the WHO is saying even outdoors, and even if you've vaccinated, avoid being in big crowds.

Nsikan Akpan: My sense is that the WHO recommendations and the CDC recommendations for outdoors and the fully vaccinated are pretty aligned, just based off of the data. I should double-check that. I'm sure somebody will fact-check me on that. [laughs]

Brian Lehrer: Here's a question coming via Twitter. It says, oh, this always happens. I start reading a Twitter question and then it disappears because we're getting so many tweets, here it is. If we got a J&J vaccine in April, should we get a Pfizer or a Moderna now, and would we even be able to get it?

Nsikan Akpan: It's a great question. We are seeing some studies showing that mixing and matching the vaccines does provide pretty solid protection. The CDC and the FDA would need to change their guidance around the Johnson & Johnson vaccine to allow for people to get a booster with the Pfizer and Moderna vaccine. I don't know if I should be recommending this, but you can always check with your doctor and see what they say. I know that there are a few prominent virologists and epidemiologists that I know have been doing that because they got a shot of Johnson & Johnson and they wanted a topper. That's one of my [crosstalk]--

Brian Lehrer: Well, in fact, one of the well-known scientists who you said in your article, Dr. Céline Gounder, who's been on the show and was, I think, an advisor to Biden, recommended that people at high risk for serious outcomes who've had the Johnson & Johnson vaccine also should get a dose of the Pfizer or Moderna. I'm curious if that would work the other way around too. If you've had one of the mRNA vaccines, Pfizer and Moderna, does anyone say it would be further productive to get the Johnson & Johnson in addition, because it gives immunity in a different way?

Nsikan Akpan: That's an interesting thought experiment. The design of the three, in terms of the part of the virus that they're targeting and how they're targeting it, are pretty similar. I would think that would be fairly overlapping. You'd have a fairly overlapping immune response. If you took two shots of the Pfizer or Moderna vaccines, and then you got a Johnson & Johnson vaccine. Yes. For sure it's going to act as a booster. Maybe that's what we do going forward. Maybe if we rely a little bit more on the Johnson a& Johnson vaccine as a booster or vice versa, we need more details from regulators to [crosstalk]--

Brian Lehrer: We should say that another piece of vaccine news this week, did you see this? I think this came out after your article, was that on, I think, it was Moderna, but then it might apply more broadly, that the immunity that you get from the vaccine would probably last for years.

Nsikan Akpan: Yes. We're seeing some really encouraging signs that the cells that are behind the immunity, they're setting up shop in our bone marrow, or they're setting up in shop in places in our bodies that typically correlate with very, very long-lasting immunity, which is a great sign. I think the thing we have to consider there though is that if the virus continues to mutate, if it continues to develop new variants, those cells that are being housed in our bodies, just because they could protect against the virus variants that they first saw, it doesn't mean that they will be able to protect against them going forward.

There's a lot to consider and there's also the main reason why people should really get vaccinated, because if we can beat back the variants that we have now, that protection will be long lasting because it'll stop mutating. There won't be any virus left to mutate.

Brian Lehrer: One more question on this track, with regular flu shot, the annual flu shot, they give people over 65 a higher dose. I haven't heard anything like that mentioned about the COVID vaccine. Do you know if that's an area of research or if there's any reason to think that would be a good idea, just larger doses of whichever vaccine for people over 65 or whatever the cutoff would be?

Nsikan Akpan: Yes. I've heard some whispers about maybe playing with the dosage, whispers about maybe playing with the timing. A lot of people have discussed boosters and when boosters might be administered. I think for sure, we might have to. When these vaccines are fully licensed, we might get to a place where we will start playing with the regiment a little bit for people who are again on the margins of solid immunity. You could see something like a booster, you could see maybe an amino stimulant potentially for some folks. I think there are a lot of open questions about how we get them the most protection out of these vaccines.

Brian Lehrer: This is WNYC FM HD and AM New York WNJT-FM, 88.1 Trenton, WNJP 88.5 Sussex, WNJY 89.3 Netcong, and WNJO 90.3 Toms River. We are in New York and New Jersey public radio, just a few minutes left with our health and science editor, Nsikan Akpan, whose article on Gothamist is called, Why the Delta Variant Matters if You're Vaccinated or Unvaccinated. Malcolm in Manhattan, you're on WNYC. Hi, Malcolm.

Malcolm: Hello, Brian and guests. Long time listener, first time caller. I'm curious as to the study you mentioned a while ago, I believe it was in England with the Pfizer for people over 50 who had been vaccinated versus nonvaccinated were experiencing more deaths. That was in England, correct?

Nsikan Akpan: Yes. That was in England.

Malcolm: Thank you. Are there any studies with the Moderna, if that's concurrent?

Nsikan Akpan: I assume studies are ongoing, but I haven't seen any real-world data yet, looking at Moderna and its breakthrough infection rate, its hospitalizations after a breakthrough infection, and deaths after a breakthrough infection. I think Public Health England, A, they really excel at health surveillance and they're doing a great job of tracking in real-time how the Pfizer and AstraZeneca vaccines are performing. They haven't started using Moderna vaccines yet. They're supposed to towards the end of this year.

Maybe we'll start getting more data from them on that. I imagine the CDC is conducting these studies and will put out some information soon because it's a really important question that people are asking.

Brian Lehrer: Dominique in Manhattan, you're on WNYC. Hello, Dominique.

Dominique: Hi. My issue is, and I keep being very frustrated about this. Why is nobody talking about natural immunity and antibodies from having gotten COVID? I had COVID at the end of January, February. I was totally and I mean, totally asymptomatic while I was taking care of my mother who was very elderly and symptomatic. I have not gotten the vaccine, I really like the way my body responded and nobody is talking about that. I am meeting people who still have the antibodies after having had COVID over a year ago. They keep saying they think they disappeared [unintelligible 00:24:38], they don't know, but nobody's talking about it. I think it's nice to be able to build up natural immunity if you're lucky enough to do that. I was very lucky.

Brian Lehrer: Dominique, thank you. Actually, it's one of the most frequent questions that we get from callers and we've asked many, many guests. We'll bring it up again now, whether you need the vaccine if you've had COVID and recovered and presumably have natural antibodies. Nsikan, you're not a Doctor, you're a PhD health journalist, so you're not here to give the call medical advice, but your article cites research from Rockefeller University on this showing some of the difference between natural immunity alone and natural plus vaccination. What did they find?

Nsikan Akpan: Dominique, I would recommend checking out the story. The recommendation is for people who recovered from a previous infection to get vaccinated. It's looking like one dose is enough to provide the maximum protection we see with two doses in people who were never infected. The reason is that, after an infection, what we see at a population level is a very wide spectrum of immune responses. Some people have very low antibodies, T-cells after an infection, some people will have a really strong immune response. Some people, the immune response lasts for six months, eight months to a year. Some people, it seems to wane a lot faster.

What the vaccination does is it puts everyone on a very strong footing. That's really important when you're facing off against variants like Delta, because Delta, what it's doing is really eroding our protection. It's really eroding our defenses. It's finding a way to squeeze through into the people who have slightly lower defenses. If you've previously recovered from an infection, especially if it's an asymptomatic infection, the recommendation is that you get vaccinated, so that way you have maximum protection against these stronger versions of the virus.

Brian Lehrer: Obviously, the conversation continues as the pandemic is not over. Hopefully, it will not become a big thing in New York with the vaccination rates that we have already, talking about the Delta variant. There are going to be breakthrough cases and some of them will be serious and the world is adjusting and the science community is adjusting. We keep needing to have these conversations. We thank WNYC health and science Editor, Nsikan Akpan, who's got an article on Gothamist now called Why the Delta Variant Matters if You're Vaccinated or Unvaccinated. Nsikan, thanks a lot.

Nsikan Akpan: Thank you.

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