As COVID Cases Rises, Effectiveness Of Vaccines Lessens In Kids

12:15 minutes

a young girl getting a vaccine shot in her right arm administered by a nurse, with a parent holding her left hand out of frame to her left
Credit: Heather Hazzan, SELF Magazine

As parts of the country continue to see waves of infection from the omicron variant of COVID-19, parents of children over age five have taken heart at the availability of vaccines—while parents of kids five and under have continued to wait for an approved dose. But even as the case numbers continue to climb, the vaccines are less effective against the more-virulent omicron variants—and, for some reason, dramatically less effective in kids. 

As science writer Maggie Koerth writes in FiveThirtyEight:

“While the original clinical trial data released in November reported an efficacy of 90.7% against infection, a report published on April 26 by the Centers for Disease Control and Prevention found that two doses of the Pfizer vaccine were only 31% effective at preventing omicron infection in 5- to 11-year-olds. In another study, which has not yet been peer-reviewed, the New York State Department of Health found that effectiveness against omicron infection absolutely tanked in this age group—down to just 12%.”

Koerth joins Ira to discuss the story, and why experts say it’s still worthwhile getting vaccinated even if the vaccines don’t have the dramatic performance seen at the beginning of the vaccination phase of the pandemic. They also talk about a bird flu outbreak troubling poultry farms around the world, the odd immune system of the sleepy lizard, and how scientists are trying to catch a whiff of the odors of ancient Egypt

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Segment Guests

Maggie Koerth

Maggie Koerth is a science journalist based in Minneapolis, Minnesota.

Segment Transcript

IRA FLATOW: This is Science Friday. I’m Ira Flatow. Later this hour, the first images of the black hole at the center of our Milky Way. But first, as parts of the country continue to see waves of infection from the Omicron variant of COVID-19, parents of children over the age of five have taken heart at the availability of vaccines. And parents of kids five and under have continued to wait for an approved dose.

But even as the case numbers continue to climb in some areas, the vaccines seem to be less effective against the more virulent Omicron variants, and for some reason, dramatically less effective in kids. Joining me now to talk about that and other stories from the week in science is Maggie Koerth, senior science writer at FiveThirtyEight. Welcome back, Maggie.

MAGGIE KOERTH: Hi. Thanks for having me.

IRA FLATOW: You’re welcome. Now, I know that you have kids, so you’re following this closely. Tell me more about the vaccine and kids. How ineffective is it?

MAGGIE KOERTH: Well, so I was really excited about this, like a lot of parents, when it first came out, because the original data was saying 90% efficacy against infection. So my kids have been vaccinated. But here is the thing– all of these vaccines have waned in efficacy over time for all of the age groups. But when you’re talking about the Pfizer vaccine in kids five to 11, it has really gone down.

In the last couple of months, there’s been two different studies, one of them by the New York State Department of Health, and the other is by the CDC. And they found that the vaccine in little kids fell to these extremely low efficacy rates against infection during the peak of the Omicron wave. So the CDC was finding 31% efficacy and the New York study was just 12%.

IRA FLATOW: Wow. So how much of this is due to these new variants being more contagious? How much is due to something going on with kids’ immune systems?

MAGGIE KOERTH: Well, it’s most likely got something to do with the Omicron variant, because we know that the efficacy against infection has fallen significantly for all age groups when it comes to the Omicron wave. But the experts I spoke with said that it’s still worth getting little kids vaccinated, even if that efficacy against infection is really low. The short explanation for that is that there is evidence that suggests the vaccines are still effective against severe illness at rates that are high enough to make it worth it, probably around 40% to 50%. It’s hard to say exactly how effective because severe illness in kids is rare to begin with. But we do know from other research that the hospitalization rate for unvaccinated kids during the Omicron wave was twice that of vaccinated kids.

IRA FLATOW: Yeah, so that’s the good news, though.

MAGGIE KOERTH: Mm-hmm. The really cool thing, though, is that what I went to talk to researchers about this, I got a better understanding of what is sort of going on with waning efficacy, which I think is just absolutely fascinating. So scientists have known for a long time that viruses with longer incubation periods have more effective vaccines, and vice versa. And that’s likely because vaccines work in two different ways.

So first, they’re producing these short-term antibodies. And then the second, they’re helping your body produce memory cells that can create antibodies down the road the next time you run into the virus. And those short-term antibodies are what is fading quickly, right? Like, those don’t last a real long time, and that’s what we see as the waning efficacy after you get your first two shots, after you get your booster.

But the memory cells are what is there for the long haul. The problem is that memory cells need time to work. So if a virus incubates in your body for a week or two before causing illness, that’s long enough for those memory cells to produce antibodies and stop illness before it starts. So that’s why you get close to 100%, 90% efficacy with things like measles, mumps, rubella, because they have these long incubation periods.

COVID is, like, a day or two incubation period. And it’s not quite long enough for those memory cells to actually produce the antibodies to stop the infection. They still produce antibodies. They stop severe infection. But it’s that incubation period that seems to be really making the difference.

IRA FLATOW: Wow, what a great lesson, Maggie. There won’t be a test on this, but I learned something right there. Parents of younger kids, under five, I know they’re concerned, and they’re still waiting for any vaccine, right? Any word on when that might be?

MAGGIE KOERTH: Right now, it sounds like June. Both Pfizer and Moderna expect to have their little, little kid vaccines ready by then. Pfizer delayed theirs in February when they figured out that the two-dose regimen wasn’t producing enough of an immune response. So they’re planning to increase to three doses. And Moderna’s trials have proven to not be very effective against infection. But again, it’s probably more effective against severe illness.

IRA FLATOW: Yeah. OK, we’ll wait to see those come out. Let’s move on to some other news. I know there’s a different epidemic going on, and this one is in birds. Tell us about that.

MAGGIE KOERTH: We are in the midst of the worst bird flu outbreak in seven years. So this is just spreading everywhere. And it’s infecting wild birds. It’s infecting birds on farms. The virus has a near-100% mortality rate among infected birds. And it’s just been spreading like crazy since the fall of 2021.

And it’s having an impact on agriculture. So already in the US, more than 37 million chickens and turkeys have been killed in an attempt to stop this thing from spreading on farms, because these farmed birds, they live in these giant barns with thousands of other animals. Once one of them gets sick, they’re all going to get sick and die. And to keep it from spreading to other barns, they’re killing them off in some kind of really horrific forms of mass chicken slaughter. We’re talking about suffocating foam in a whole barn or just shutting off the ventilation and letting all of the birds slowly overheat.

IRA FLATOW: Oh, my goodness.

MAGGIE KOERTH: I know. It’s kind of wild. But it’s also meant that some of the birds that had better lifestyles, that were free-range, have had to be moved indoors so that they can be kept away from wild birds and kept away from birds in other parts of the farm. So this is spreading so rapidly, the best way to keep it from killing these domestic birds or having to kill them yourself is to just not let them have any contact with other birds. So these chickens are basically going on lockdown.

And in France, that became mandatory back in November. And the UK has even had to change its egg labels so it doesn’t say “free range” anymore. It says “barn eggs.”

IRA FLATOW: Oh, that’s interesting. So you can’t market them as free range, because people are looking for those kinds of birds, those kinds of eggs.

MAGGIE KOERTH: Right. They can’t really be free range right now.

IRA FLATOW: Wow. You know, when you hear bird flu, one of the things that comes to mind is the possibility it might jump to people with all those millions of birds. I mean, have we seen any sign of that yet?

MAGGIE KOERTH: So there have been people who have caught this, but they are– it’s not been really severe illness. And it’s only been in people who had lots of contact with the birds. So for instance, one of the people who caught it in the US is an inmate at a prison who had been working as part of a work release program culling some of these birds on chicken farms.

IRA FLATOW: Let’s go on to something a little bit lighter, a story you point out about some cool rock formations on the seafloor.



MAGGIE KOERTH: Ocean rocks– they’re awesome. So there is this remote conservation area in the Northern Pacific where only 3% of the sea floor has been mapped. And scientists are working on this project using remotely-operated submarines to explore down there. And they’ve been livestreaming their discoveries on YouTube. And this last week, they stumbled across something really cool, which is these cracked rocks that end up looking like a paved brick road.

IRA FLATOW: Not yellow brick.

MAGGIE KOERTH: No. I mean, kind of greenish gray brick, from what I’ve seen in the video. And definitely not the road to Atlantis. That was just a joke that one of the researchers made on the livestream.

IRA FLATOW: Oh, is that right? They were joking.

MAGGIE KOERTH: Yeah. But this is rock that’s called hyaloclastite. It’s a glassy volcanic rock, and it’s produced when lava comes into contact with water or ice and just cools really rapidly. And this formation, then, has been fractured over the years as this other nearby volcanic activity heated it and cooled it over and over again. So you get all of these really interesting crack patterns going one way or the other, and that’s what makes it end up looking like bricks.

IRA FLATOW: Really interesting. Speaking of interesting geology, there’s word that scientists have been experimenting with samples of lunar regolith, or what we might call lunar dust, soil. What’s going on there?

MAGGIE KOERTH: So NASA-funded scientists grew plants in lunar soil. And this plant in question is a relative of mustard and broccoli. And it’s really, really teeny, so we’re talking about something that is small enough that it could grow in only a gram of regolith per plant.

But these scientists grew these seeds. They put the seeds in there with water and nutrient solution. And they had these little teeny, tiny vials. And part of why it’s so small, why we had to do something so small, is we just don’t have that much regolith on Earth at present. The stuff these plants were grown in literally came from the Apollo 11, 12, and 17 missions.

IRA FLATOW: You know, my definition of soil is it has to have organic matter in it. And certainly, lunar regolith doesn’t. So were the plants stunted? I mean, they didn’t grow as much as they would here on regular soil, would they?

MAGGIE KOERTH: No, they did not. So they were compared to plants grown in some boring old Terran volcanic ash. And they did not do as well as the ash-grown plants. So they grew more slowly. They had less well-developed roots. Some of them even had these little funky reddish, stunted leaves.

So the good news here is that, yes, you can grow plants in moon soil. And the bad news is that they are not going to be as good of plants is what you get on Earth. And we don’t really know why yet. So this is just a first step to further research, and it’s stuff that we need to figure out if we are really serious about building new and permanent moon bases.

IRA FLATOW: Speaking of moon bases and the astronauts that might go to them, if you talk to astronauts, they’ll tell you that things can get kind of stinky in their enclosed capsules after a while. But you point out–

MAGGIE KOERTH: This is a great transition.


IRA FLATOW: I’m working hard at it. But you point out a story about researchers trying to recreate the smells of ancient Egypt. What’s that about?

MAGGIE KOERTH: Yeah. So I love this. Bruce Bauer at Science News has this story about a variety of different ways that scientists are trying to get a better understanding of the smells of the ancient world. And it’s being done in several different ways by different teams. So some people are sampling molecules of organic material off of physical artifacts and analyzing the chemistry of that to figure out what these molecules came from.

And they’re finding things like frankincense and myrrh left behind on incense burners. They’re finding things like dried fish and barley flour in ancient jars at the molecular level. And so we can kind of know these are smells that existed thousands of years ago. Another team has even tried to recreate Cleopatra’s perfume.

IRA FLATOW: Are we going to see that on the market by Christmas, do you think?

MAGGIE KOERTH: I don’t know. It’s supposed to smell really nice, something kind of spicy sweet– date oil, myrrh, cinnamon, and pine resin.

IRA FLATOW: Maggie, let’s end on that sweet-smelling note today. Thank you for taking time to be with us today.

MAGGIE KOERTH: Absolutely. Thank you.

IRA FLATOW: Maggie Koerth, senior science writer at FiveThirtyEight, based in Minneapolis.

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