Almost half of all Americans have now received at least one COVID-19 vaccine dose and roughly 40% are fully vaccinated, making mask mandates a thing of the past. Already, more than half a dozen states have vaccinated more than 70% of adults with at least one dose and some counties are hitting vaccine rates as high as 90% for those over 65 years of age.
As we've watched deaths from COVID drop across the country, it seems we are getting closer to the goal of the pandemic response: getting a high enough percentage of people with immunity to return to "normal." While all signs seem to point to us being closer to that goal, will it also signal the end of the pandemic? After all, herd immunity is a global effort and dozens of countries haven't even vaccinated 5% of their population.
Tom Frieden, MD, MPH, the former CDC Director under President Obama, and current president and CEO of Resolve to Save Lives, joins us on this week's episode to explain if we'll get there or if our goal should be something else completely.
The following is a transcript of his interview with "Track the Vax" host Serena Marshall:
Marshall: Dr. Frieden, herd immunity. It's something everyone is talking about these days.
Frieden: Well, I think there's actually a miscommunication. And the fact is it's not like a light switch: you have herd immunity and suddenly magically COVID is gone. The way immunity works is the more we build up in the population, the fewer outbreaks there will be. Unfortunately, what we're seeing in the U.S. is some pockets, demographic, geographic, even ideological, which are getting much less vaccination coverage.
And in those pockets, we're likely to continue to see clusters and potentially outbreaks.
Marshall: I want to dive into those pockets in just a few minutes, but let's first dive into what you just said. There's no magic light switch, no abracadabra. We think about herd immunity though, and we think about things like measles or smallpox that have gone away because we've reached herd immunity. But in the timeline we're in right now, that's taken decades to reach.
Frieden: Smallpox is a special case. It's the only human disease that has been eradicated. And we're not about to eradicate COVID. It's going to be with us for the indefinite future. We're going to have to learn to live with it and help people not die from it. And that means ramping up vaccination. And as there are fewer cases getting better at stopping cases in clusters from spreading, particularly because of the risk of more dangerous variants.
We've already seen variants that are more infectious and likely more deadly, and that's potentially just a warning of what could be coming in the future. There may be even more deadly variants coming. And so it's really important that we vaccinate better and do a really good job of finding cases quickly and stopping the spread.
Marshall: And then given those variants that you just mentioned, is herd immunity even realistic at any point in the future when it comes to COVID?
Frieden: I think there's some very positive things that we're seeing around the world. What we see in Israel right now is high levels of vaccination and basically, largely, back to normal. They continue to mask in schools because of course kids don't have approved vaccines yet, but they're dining. They're going to restaurants and bars. They've got theaters open. And, generally, they're seeing what life will be like when the worst of the pandemic is over. And I think we'll be there in the U.S. with a much better situation over the summer and we'll be at the new normal in the fall.
Marshall: Now some counties, though, are even projecting they'll reach herd immunity sooner than the fall... even beginning of June. LA County, by the end of July.
I mean, are those realistic expectations for those counties? And especially given the fact that one county might have herd immunity. And you mentioned a second ago, the pockets and another might not.
Frieden: I think the fact is we're going to have to keep our guard up. That doesn't mean we're going to have to keep business closures in place. I think we should be able to open virtually all businesses and schools in the fall. And even over the summer in many places. The more we vaccinate the better off we'll be.
It's crucially important though, that we get doctors more in the game on vaccination. There are still tens of millions of people at high risk for COVID who haven't been vaccinated. That's a risk of death. That's a risk of burden on our healthcare facility and that's a risk of uncontrolled spread that could lead to the emergence and spread of even more dangerous variants.
Marshall: What does herd immunity actually look like or mean? Is there a number that you can quantify for us? I mean, we've heard that 70% to 80% of the population, but when you're looking at different communities, different, as you said, ideologies. Different vaccination rates. How do you quantify that number?
Frieden: One thing that's really important to understand is that herd immunity is proportional or... the R0 which everyone's gotten to know what it means now.
Marshall: The naught?
Frieden: I prefer to call it the R0 because we're in the U.S. but everyone else calls it the R-naught.
The R0 for measles is very high, 15 to 20. And so to get good immunity against measles, you need well over 90% of the population immune through either infection or vaccination. With the variants, we're seeing much higher infectivity. And because of that, we need to get even higher levels of vaccination.
So we have two unfavorable developments. One is that there's a slowing of the vaccination pace. And the second is there's an acceleration of the spread of the virus. And that doesn't mean that all is lost. That doesn't mean we're going to go back to worst days. The worst of COVID is behind us in the U.S.
It does mean that we need to keep our guard up. It means that we need to continue to think of COVID, detect it. Isolate people. Provide COVID support services to those who are infected and continue to reach those who haven't been vaccinated with the messages and the messengers who will be most effective, especially their clinician.
Marshall: You mentioned the R-naught and how the variants are changing that number. I mean, measles were able to get such a high R-naught, or R0 at 90% because we vaccinate children. Children aren't yet included in the vaccines for COVID. Now we're starting to move forward with the over 12 age group. But when you look at the percentage of the population that kids make up, you know, 20% or so. So how do we even hit that 70% to 80% number if we don't have full kids and get to herd immunity and have things open up by the fall?
How is that actually possible or is it not?
Frieden: Well, first off, just to clarify about measles. One of the remarkable things about measles is if you get measles, you are almost certainly going to be completely immune for the rest of your life. So natural immunity.
Marshall: That is a big difference from where we are now.
Frieden: That is a big difference with measles. And even with measles, measles continues to kill a hundred thousand kids around the world every year.
And continues to cause clusters and outbreaks in the U.S. and that's a reflection that infectious diseases are going to be here with us. And I do think though, first off, when you get the most vulnerable people vaccinated, even if COVID is spreading it's not going to be causing the kind of devastating disease that it caused in the U.S. for much of the past year plus.
Second, you won't have explosive spread in communities, if you have high levels of vaccination. And that's why I don't say we're going to be back to normal in the fall. I say we will be at the 'new normal.' That new normal may include, for example, you go to a theater and everyone's wearing a mask just to be on the safe side.
You are going to be in one airspace for two or three hours with hundreds of people? Makes sense to wear a mask. Come flu season it may be a really good idea to wear masks because it'll reduce influenza and other diseases. If you have an underlying condition ... Probably not a bad idea to wear a mask if you're on the subway.
So it will be a new normal, but the key is that our economic and educational environment will continue, and will be robust. We can get back to the things that we miss, we need to do, and we love to do.
Marshall: The kids' role in herd immunity and getting kids vaccinated. Is there going to be a moment where we have enough younger kids, enough kids under the age of 18 vaccinated to help with those who are hesitant in the adult population?
Frieden: I think the more people who get vaccinated the better. And having vaccines available for our kids helps us get schools reopened. It will help reduce the spread in the community. But if you look at Israel and other places around the world, even without vaccinating kids, it's possible to get to a good situation. With kids getting vaccinated we can get to an even better situation.
Marshall: Now are the variants the whole reason, though, for this kind of moving target when it comes to that herd immunity and the ability to hit it?
When the pandemic first got underway, people talked a little bit about herd immunity. As we started to ramp up vaccinations, we talked more about herd immunity, and now it seems to be that, you know, we're probably not going to get to herd immunity.
Frieden: Again, I think there's a misconception of what herd immunity is. It's not eradication where the disease is gone. What we expect is that we get a high enough rate of vaccination, so we will not have widespread, explosive outbreaks of COVID. We will still be at risk for outbreaks in institutions; homeless shelters, correctional facilities, nursing homes, housing projects, even schools and universities.
That's why we need to continue to ramp up vaccination. That's why we need to continue to test and provide support to people who have COVID so that they stop spreading it to others.
Marshall: Now, let's talk for a second, Dr. Frieden, about natural immunity and its impact and role in achieving some kind of herd immunity. When we talk about herd immunity, we hear mostly about vaccines, but are they including that natural immunity as a factor in those discussions?
Frieden: There's still a lot we don't know about natural immunity. There's at least one study that suggests that among the elderly, there's quite a bit of fading of natural immunity after 6 to 9 months. We're not certain that that's correct, but it could be.
Interestingly, unlike many vaccines... take measles, which you've mentioned. The measles vaccine is good, but not nearly as good in giving you immunity as getting measles.
You get measles. You're not going to get it again. We need two doses of measles vaccine. And even after that, there are some breakthrough measles infections. In contrast, with COVID, especially for the mRNA vaccines, the Pfizer and Moderna vaccines. These have really superhuman immunity. By which, I mean, the level of immunity you get with these vaccines is much higher than our natural immunity from everything we know so far.
And that's why I've been concerned that some of the companies are speaking very confidently about -- that we'll definitely need booster vaccine doses. We may, we may not. We have to wait to see what the science shows.
Marshall: Dr. Frieden, you just mentioned the 6 to 9 months of natural immunity after infection, but we're only getting to that 6-month mark now with the vaccine. So how are we able to say so definitively that the immunity from the vaccination is in fact higher than natural immunity?
Frieden: What we see is that the antibody levels and neutralizing antibody levels are much higher with the vaccine than they are after infection with the virus. Furthermore, if you look in those first 6 months, the level of protection against all infection and against severe infection is 90-95% or higher.
Interestingly, if you look at the clinical trials, there were some people who had prior infection and who got the placebo, they had about an 80% protection against getting the virus again. So it does look like the vaccines provide stronger immunity than natural infection.
How long that immunity lasts in some ways only time will tell because we don't have any perfect test to see whether you're immune with a blood test.
Marshall: Is that something that will be needed though, to get to a herd immunity or that new normal as you described it?
Frieden: We don't know whether booster doses will be needed. If new variants emerge that get around the vaccine induced immunity, then we might need a variant specific booster. If our immunity wanes in months or years or decades, then we might need a booster. We really don't know at this time.
It's absolutely right that the companies are making boosters and studying it, but it's not going to be the companies. It's going to be science and independent advisory committees that determine whether or not a booster is needed.
Marshall: So how will Americans know that we've reached herd immunity? Is it when they get that announcement from the County health department? Like what L.A. is saying, for example, the end of June?
Frieden: I do not think that a sensible way to think about this is: are we there yet for herd immunity. Herd immunity isn't like a herd of Buffalo that has just stampeded into town.
I would rather think of what we call a risk alert level, but right now...
Marshall: That's a new term that we're going to be using?
Frieden: I think so. And it's similar to what we see with ozone levels or the risk of wildfires or the risk of particulate matter or smog in your environment. Basically think of a four level system: red, orange, yellow, green. And when it's raining COVID out, you may want to wear a mask on the subway. When it's not, you probably don't need to, unless you have an underlying condition that may make you more susceptible to severe illness.
I think we have to respect and come to terms with a greater granularity of reality here. Right now very few counties in America are at a low level of risk for COVID. I think by summer, many more will be. And by fall, most will be.
Marshall: That'd be a big mental shift. I think for many Americans to think, well, I'm getting the vaccine to help herd immunity, to help those who may not be able to get it who are more susceptible. And now I still have to think about what the COVID spread is in my community after vaccination?
Frieden: You're getting the vaccine to save your life and the lives of people around you. And just as, you know, it rains sometimes. And just as we have flu season, we will have times when there's COVID risk. But if enough of us get vaccinated, that risk will be quite small.
Marshall: And you mentioned earlier though, that there's the possibility, and I know it's a slim one, that there could become a variant that gets around these vaccines. So, you said that boosters could be necessary for it, but does that mean we're going to have to kind of start at square one when it comes to reaching a type of herd immunity?
Frieden: No, actually what we're seeing is that the variants that have emerged so far are similar enough so that even if there is some vaccine -- what's called vaccine immunity escape -- of a new variant. We would be boosting our prior immunity from infection or prior vaccination. So it's not that you we are back to zero.
Quite the contrary. We're close to the finish line, if you will. And we just need a little boost to get us there.
Marshall: You mentioned the pockets of hesitancy. We know that that exists, especially among the deep South. Even if a neighboring state gets to that level where they're spread is low and they have enough vaccination in their state.
With that neighboring state having a high transmission and a low rate of vaccination. Do they need to be concerned about it impacting their immunity levels?
Frieden: I think the biggest concern is that uncontrolled spread anywhere, anywhere in the U.S., anywhere in the world, carries with it the risk of the emergence, and then spread of even more dangerous, even more deadly variants. That's the primary risk. But if a community is well vaccinated, that community is well protected.
This is not just a question of individuals. If you're vaccinated, you're well protected against COVID. If most people around you are also vaccinated. You're superbly well-protected against COVID.
One of the things that's been hard to convey to people through this whole pandemic is that whether we like it or we don't like it, the fact is, that we are all connected and that what one person does affects other people. Whether it's about masking or vaccination or getting tested or not traveling when COVID is spreading explosively. We are connected.
And even though I do believe with a high level of confidence that we're going to be in a good situation in the U.S. by the fall. Unfortunately, that is unlikely to be the situation globally, because there's not enough vaccine globally because there's uncontrolled spread in countries all around the world. And that is a risk to all of us.
Marshall: I'm really glad you brought that up, Dr. Frieden. We spoke to Dr. Nahid Bhadelia previously on this show, and she had mentioned, you know, everywhere in the world nowadays is two flights and a bus ride away. So will herd immunity in the U.S. mean that we're in a silo, in a bubble. And you just hinted at that it definitely does not. But how would that spread globally impact herd immunity here in the U.S.?
Frieden: If we are unable to increase access to vaccines globally. We're going to have a problem. We're going to have a problem because there's going to be less travel and trade. We're going to have a problem because there will be instability, social, economic and political, around the world. We're going to have a problem because there's going to be an ethical problem.
People will be going to the movies in the U.S. While, body bags are stacking up in other countries. And we're going to have a problem because uncontrolled spread anywhere in the world raises a real risk that there will be even more dangerous, even deadlier variants that emerge and spread, including in the U.S.
That's why it's so important we scale up global manufacturing and we provide vaccines as quickly as possible to countries all over the world. We're all in this together. There's only one enemy here. That enemy is a virus.
Marshall: When do you see global herd immunity or global code -- you said a four level system, right? So perhaps yellow or green globally?
Frieden: I think that very much just depends on how quickly vaccine manufacturing is scaled up. You have two camps here. One camp that says open the intellectual property and let people make, or companies make vaccines. On the other hand, you have companies saying: trust us, we're going to make enough vaccines for everyone.
I don't think either of those camps have it right. I think what we've got to do is engage with companies, open intellectual property, establish vaccine manufacturing hubs that can rapidly scale up the amount of vaccine. And train more manufacturers to scale it up. This is a global pandemic and until the global pandemic is over, we will not be back to normal in the U.S.
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