IRA FLATOW: You know, it either seems like yesterday or a very long time ago, but it was actually two years ago today that the WHO declared COVID-19 a pandemic. Later this month, Hawaii will become the 50th and final US state to drop indoor mask requirements. Those and other COVID-19 protections have been tumbling down nationwide, as the winter Omicron surge has eased.

But case numbers are still going up elsewhere in the world and signal a virus that is far from finished. Here with more on this and other recent stories is science journalist Roxanne Khamsi. She joins us from Montreal, Quebec. Welcome back, Roxanne.

ROXANNE KHAMSI: Hi, Ira, it’s great to be back.

IRA FLATOW: Nice to have you. OK, let’s get right into this. We really have seen a lot of COVID-19 protections taken down in the US in the last couple of weeks. What reasons have been given for this?

ROXANNE KHAMSI: Well, yeah, it’s true. So recently, the CDC said that 98% of Americans live in locations where you don’t have to wear a mask indoors if you don’t have any predisposing conditions that would put you at extra risk.

And part of that is because they have determined that enough people have immunity and they’ve also changed the calculus in terms of what is a high-risk environment. So they’ve kind of highered the threshold of the number of cases that makes a place a high-risk location.

IRA FLATOW: Yeah. It’s not just the US dropping protections either, right? Other countries have.

ROXANNE KHAMSI: No, a whole bunch of countries have.

IRA FLATOW: Yeah.

ROXANNE KHAMSI: The UK has. And Austria recently backtracked. There was a mandate that was about to go into effect for people to be mandated to be vaccinated and recently lawmakers took a step back and said, actually, we’re not going to enforce that. So there’s definitely a walking back of restrictions and things like that in a lot of places, not just the US.

IRA FLATOW: On the other hand, there are places where case numbers are definitely not going down. We’re watching the numbers go up.

ROXANNE KHAMSI: So absolutely. This is happening at a lot of places where they had a COVID zero policy. So they had really been successful in keeping the virus at bay for months, and months, and months.

Some place like Hong Kong, the highest number of cases of COVID that they had in a day last year was 60. And now they have tens of thousands of cases a day and I think around 250 people a day dying, which for a place with not a huge population is an extremely high number. And China seems to also be perhaps heading in that direction too.

IRA FLATOW: We’ll have to look into that in great detail as we go on in the months. There’s also a sub-variant of Omicron beginning to circulate more widely, right?

ROXANNE KHAMSI: Right, exactly, BA2. And I think what’s interesting is there’s been a huge consensus that it’s more transmissible than the original Omicron variant. What seems to be still in debate is whether it’s more dangerous. A lot of people say, no.

IRA FLATOW: Yeah.

ROXANNE KHAMSI: Some people say, yes.

IRA FLATOW: Yeah.

ROXANNE KHAMSI: But, yeah, so we’re not done with variants by any means. The story is not over at all.

IRA FLATOW: Yeah, we’re not done with the virus. We’ll get into that a little bit later also, but let’s move on to other infectious disease news, especially polio. Polio has been close to eradication for years now, but we’re still not there, right? A few weeks ago we talked about its reemergence in Malawi– Malani– Malawi. And now, the Russian invasion of Ukraine may be further jeopardizing the end of this virus. Why is that?

ROXANNE KHAMSI: Well, I think this is a really interesting and somewhat, in a way, sad story. So the polio eradication campaign launched in 1988. And it’s possible because polio doesn’t have an animal reservoir. Unlike SARS-CoV-2, it really just happens in humans. And of course, can cause paralysis and really horrible effects. But by 2017, there were only 17 cases of polio in the world, which was a great achievement.

IRA FLATOW: Yeah.

ROXANNE KHAMSI: And then in recent years, in places– particularly war-torn torn places, like Afghanistan and other regions like that, it’s been creeping up. And as you mentioned, in Ukraine there was an uptick in polio, where there were two kids that got paralyzed with polio not that long ago, the last case being in January.

And it indicates that the virus is still circulating there. And that with only 50% of kids under one vaccinated against polio there, and the war now happening, just totally disrupting vaccination campaigns, there’s a huge worry that this is going to set back this campaign to eradicate polio, which has until recent years been such a success story.

IRA FLATOW: Yeah, because we do have very effective of vaccines for it.

ROXANNE KHAMSI: Absolutely. I mean, there’s two different kinds of vaccines. One is given orally. It’s like a drop in the mouth. And then the other one is in a shot. And there’s different strategies. The one that’s given as drops in the mouth is more feasible to be given in conflict regions. Of course, the downside is it’s not quite as effective as the shot.

IRA FLATOW: Right, right.

ROXANNE KHAMSI: So.

IRA FLATOW: Right.

ROXANNE KHAMSI: Yeah.

IRA FLATOW: Yeah. We’re actually going to go back to a story now that you brought us two months ago, when it was reported that a man had received a heart transplant using the heart of a genetically modified pig. But the update is a sad one, is it not?

ROXANNE KHAMSI: It is a sad one. And I’m really sorry to bring this news, but the patient, David Bennett, who received the pig– sorry, that received the heart from a pig, unfortunately passed away this past week. And the doctors who did the transplant aren’t quite sure what happened.

They don’t know if his body rejected this heart that had been so specially tailored to not be rejected by his body, by these genetic modifications in the pig that it came from. They’re putting together a report.

But for him, it was really like a last resort option. He didn’t have– he was too sick to receive a human heart, to be on the– to be in a place on the wait-list where he would receive a human heart. So this for him was kind of the last opportunity.

IRA FLATOW: Yeah.

ROXANNE KHAMSI: And unfortunately, it didn’t work out.

IRA FLATOW: We’ll have to wait and see what– they haven’t published their findings yet, but we’ll have to wait and see for that.

ROXANNE KHAMSI: Yes, absolutely.

IRA FLATOW: Onto something a little bit different. History nerds, we are excited this week at the announcement that the ship of explorer Ernest Shackleton has been discovered, more than a century after it was lost to crushing Antarctic ice. I mean, I was– as someone’s who’s been to Antarctica, that’s all they talk about when I was there, is how brave and smart he was. This is thrilling to see. And there are video– there’s video of this.

ROXANNE KHAMSI: Yes. It’s also– it seems surreal in some ways. I know we’re on the radio, so people can’t see what we’re talking about. But it looks like somebody just dropped it there yesterday, when in fact, it’s been there for 107 years.

IRA FLATOW: Yeah. Yeah.

ROXANNE KHAMSI: Part of me wonders if it’s so well-preserved because it’s in this cold area, which is, of course, also why it was so hard to find. If you listen to the researchers who found it, talking about the journey to uncover where it actually was, they talk about snowstorms, ice storms, all sorts of elements that kept them from being in the right place to drop this device, this robotic device under the ocean to search.

So– but, yeah, so they’ve uncovered “The Endurance,” which Shackleton had been– had set out with to try to traverse Antarctica, after missing out on being the first person to get to the South Pole. And– and 3,000 meters under the ocean, under the sea there, it sat for 107 years, until today, they found it.

IRA FLATOW: It’s only fitting that it took so much effort to get it because he took so much effort to save all of his crew. No one– no one died in that rescue. It’s an amazing story, but it’s too long for–

ROXANNE KHAMSI: It’s amazing.

IRA FLATOW: –to tell. Go– go google it. It’s– it’s unbelievable. One last story–

ROXANNE KHAMSI: It’s amazing. Yeah, I was just going to say they kind of camped out on the ice–

IRA FLATOW: Right.

ROXANNE KHAMSI: –for months before they could get to safer– safer ground with lifeboats.

IRA FLATOW: And then there was this 800-mile trip in a lifeboat that went to an island where they could try to bring back some rescue people.

ROXANNE KHAMSI: It’s incredible.

IRA FLATOW: And they did it. It’s an incredible– incredible feat. One last story, just in time for daylight savings. Because that’s happening this weekend– who knew so quickly? You’ve got a story about Stonehenge.

ROXANNE KHAMSI: Who doesn’t love Stonehenge?

IRA FLATOW: We all do, right? It’s mysterious. We think it might have told time somehow. And now someone thinks they figured out exactly how. What’s the deal here?

ROXANNE KHAMSI: Right, and you’re totally right, this is just perfect timing, because we’re all going to set our clocks back an hour– or sorry, skip ahead an hour. I can never keep track of that. And so Stonehenge used to be thought of as kind of built around the solstices– winter and summer. But a reanalysis have looked at the stones and said, actually this might be a solar calendar, kind of not too dissimilar from what we have today. We have 365 days and then a leap day every four years. This was 365.25 days, similar to what the Egyptians had figured out a couple centuries before.

IRA FLATOW: Wow. I want to throw in a bonus story that you have for us today. That’s something about researchers finally talking about sharks sleeping– sharks.

ROXANNE KHAMSI: The only kind of shark I ever want to encounter is a sleeping shark.

IRA FLATOW: Well, because I remember being a scuba diver, that they said the sharks are sleeping, they’re not moving, but they have to keep the water moving past their gills so that they can still breathe. But they do sleep, is that what we’re finding here?

ROXANNE KHAMSI: Yeah, so this is a study that was done on a particular kind of shark known as a draft spore shark, which it gets its name from its checkered external– I guess skin is what you’d call it. And scientists had an idea that sharks slept, but they weren’t really sure. No one had put them in a tank to observe and find out.

So they did this. And using certain physiological measures, like how much oxygen they were consuming, and also, interestingly, their eye movements. They appeared– so they determined that when they were sleeping, they were using half as much energy as when they were resting. And also, that they had a different position. So they were flatter when they were sleeping, as opposed to a little bit more upright. So they kind of had their torsos perked up when they were resting a little bit more, like one of these yoga positions.

IRA FLATOW: Now I’ve heard it, I can’t get it out of my mind. I’m going to think shark yoga next time I’m on my mat. And especially with breathing, right– that’s what yoga is all about. We know that sharks–

ROXANNE KHAMSI: Yes, and resting.

IRA FLATOW: And resting.

ROXANNE KHAMSI: And restorative-ness, yes.

IRA FLATOW: Terrific, Roxanne. Thank you for taking time to be with us today. Great stuff.

ROXANNE KHAMSI: Great. Talk to you later. Thanks, Ira.

IRA FLATOW: Roxanne Khamsi is a science journalist based in Montreal.

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