IRA FLATOW: This is Science Friday. I’m Ira Flatow. A little bit later in the hour, why the Audubon Christmas Bird Count is still sending you out into the snow more than 100 years after its inception. And yes, the answer is data.

But first, the US set a global record this week, the highest number of new COVID cases in a single day, about one million, mostly driven by Omicron. The highly contagious variant accounted for about 95% of new cases last week. And to top it all off, tests are in short supply, the CDC changed its quarantine guidelines, and some schools have returned to remote learning.

To help us make sense of the latest Omicron news is virologist Dr. Angela Rasmussen. She’s a research scientist at VIDO-InterVac, the University of Saskatchewan’s Vaccine Research Institute in Saskatoon. Welcome back to Science Friday. Always good to have you.

ANGELA RASMUSSEN: Thank you so much for having me back, Ira

IRA FLATOW: In South Africa and parts of Europe that have already been hit by Omicron, cases have surged and then, what, they’ve dropped pretty rapidly? Do you expect Omicron– the wave in the US– to crest and fall more quickly than we’ve seen in the past?

ANGELA RASMUSSEN: So, I do. But the caveat, here, is that it’s not going to happen all at once. So Omicron, as we’ve seen, it’s surging in several major cities. But it hasn’t really leaked out to the entire country at the same rate. So each of those individual communities is going to have a peak that occurs at a different time.

So even though the individual peaks within a community or a region that’s affected will hopefully go faster than previous surges have, nationwide it’s going to actually seem like it’s taking a little bit longer, because there will be different communities all peaking at different periods of time.

IRA FLATOW: I know that you co-authored a report with the organization Prep for All that estimates we need– I had to read this number a couple of times– we need 22 billion more additional vaccine doses?

ANGELA RASMUSSEN: Yeah that’s our contention. And the reason that we came to this conclusion is that, while it’s true that many countries in the world have been vaccinating people at a fairly brisk clip, there are still 3 billion people worldwide that haven’t had a single vaccine dose. And many of the other vaccines that have been distributed worldwide are not the mRNA vaccines. So they’re vaccines that are either not authorized in the US, such as the Sinovac inactivated vaccine, or vaccines like the AstraZeneca vaccine, for example.

Now any vaccine is better than no vaccine. I want to be clear about that. But as we’ve seen with Omicron, the mRNA vaccines really do seem to be eliciting broader immunity, meaning that the immunity that’s elicited is more cross-protective against multiple variants than some of these other vaccines. And overall, particularly with an mRNA booster, the vaccine effectiveness is higher against both infection, even though it’s not 100%, as well as protecting against severe disease.

So our contention is that people should not necessarily be considered fully vaccinated if they’ve had two doses of one of these other vaccines that doesn’t provide as strong a protection as the mRNA vaccines do. And the entire world really should be allowed to have access to the same vaccine benefits that we are getting in the US, and in Canada, and in Europe, and in other countries around the world.

IRA FLATOW: Is the thinking here, not only to vaccinate these people, but to prevent or slow down the development of another variant in people who are not vaccinated?

ANGELA RASMUSSEN: Well that’s absolutely right. And I think that this is the one thing we can expect. As long as there are significant populations of people out there, and that includes within the US– there are still quite a few unvaccinated people in the US– as long as there are susceptible populations, the virus will continue to spread. The virus will make new variants, and potentially any of those could emerge as a new variant of concern.

IRA FLATOW: Now I know that the CDC recently changed its quarantine recommendations from 10 days down to five days. And then people are supposed to wear a mask for five days afterwards. And then they amended the guidance this week, saying that people can test, if they want, after five days. This is all very confusing. And I know you and other scientists have been vocally opposed to this change. Tell us why.

ANGELA RASMUSSEN: Yeah, so this has been really, really frustrating simply because it is so confusing. I understand where the CDC is coming from in making this recommendation. There is a real risk that a bunch of people, including fully vaccinated people, are going to be getting Omicron at the same time. And that’s going to have a profound, potentially, impact on essential services. So this guidance was really formulated to prevent that from happening.

Now five days– in many people, they will no longer be shedding enough virus to pose a transmission risk to others. And that’s sort of the assumption that this recommendation was based on. However, that’s not going to apply to every individual person.

And the other issue is that those assumptions are being based on prior variants. The one thing we know with Omicron is that the kinetics of infection are very different. This thing spreads incredibly quickly. And we don’t really know when the peak times are that people are going to be contagious. We haven’t collected that information at a robust enough level to, I think, make those conclusions.

The other thing about this guidance is that it really does assume that people will be wearing those masks, and they will be wearing good quality masks that are well fitted, for those full five days. And that includes at home, sometimes within their own households, if there’s people in their households who have not tested positive. And I think that’s just a really big ask.

I mean, I think the issue that me and many of my colleagues had with this was there was no mention, initially, of taking a rapid test to potentially see if you might be shedding enough virus to pose a transmission risk to others. And part of this is that we simply just don’t have the supply of rapid tests. But that’s actually also not a responsibility that should be passed on to the public. I’d really like to see more engagement with the fact that we don’t have enough rapid tests, and in efforts to improve access to those tests, rather than to just say that they’re, first, unnecessary, and now they’re kind of optional.

IRA FLATOW: But could a rapid test give you a false sense of security if you take it too early, right, when there’s not enough to test for.

ANGELA RASMUSSEN: Yeah, it certainly could. And so rapid tests are by no means like the end-all, be-all solution to this. They certainly have their limitations. And one of those limitations is sensitivity. But that is why rapid tests can also be very useful for somebody who wants to determine if they’re no longer a threat to other people.

If you’re still shedding enough virus to be detectable on a rapid test, that does indicate that maybe you should continue isolating, because you might pose a transmission risk to others. I think that not including a component helping people to understand how to better use those rapid tests has really been a real mistake

IRA FLATOW: Should asymptomatic people get tested?

ANGELA RASMUSSEN: So yes. People do tend to spread COVID 19 prior to becoming symptomatic. So that means that to catch cases as early as possible, you really do need to be routinely screening asymptomatic people. And that really is one way that rapid tests could potentially be very beneficial, is if you don’t have any symptoms but you think you might have been exposed, and you just want to know if you might present a risk to people before you go out and meet with them. Then you can take a rapid test, whether you’re symptomatic or not. And if you test positive, then obviously you should rethink your plan

But I know that, because of the shortage of tests, a lot of people are saying now, well we can only spare tests for people who are symptomatic. And this is problematic for a number of reasons. Not only will it potentially allow some cases to slip by our notice, but it also could impact the way that people can access treatment.

So the new coronavirus antivirals that have been authorized by the FDA require a confirmation of a positive COVID PCR test. If people can’t get that PCR test within a reasonable frame of time, then they may actually age out of the window in which those drugs can be prescribed. Because they can really only be prescribed within five days of diagnosis or symptom onset. Otherwise they’re not very effective.

IRA FLATOW: I want to move on, briefly in the time we have, to talk about schools. Schools all over the country have been extending winter break a week longer, or switching back online schooling because of this Omicron surge. Is that the best approach right now, to keep schools closed?

ANGELA RASMUSSEN: Boy Ira, you just ask me all the easy questions. This is something that–

IRA FLATOW: That’s why I sit here and you sit there.

ANGELA RASMUSSEN: Exactly. This is something– this is a question that there’s really no good answer for. Because a lot of it is really going to depend on the types of mitigations that are in place, not just even in a given state or a given school district, but sometimes in a given school. Sometimes in a given classroom. It’s going to depend on how many of the staff has been vaccinated. It’s going to depend on how old the kids are. Obviously, kids under the age of five can’t be vaccinated. It’s going to, then, also depend, of kids who are old enough to get vaccinated, on the vaccination rate of the students. And it’s certainly going to depend on the prevalence of Omicron in that community.

So in some places, absolutely, I think it’s a wise idea to pause schools. This is not saying that schools should go back to being remote all the time. But I do think that, where you have extremely high community prevalence, where you don’t have good effective mitigation measures in schools, and where you may have a lot of vulnerable people in the community, whether they’ve been vaccinated or not, it is a smart idea, potentially, to consider pausing in-person classes.

I recognize, certainly, that children benefit immensely from going to school in person. But at some point you have to look at the potential harm. And that harm would be, in this case, measured by hospitalizations and deaths in a community versus delaying the onset of in-person classes.

IRA FLATOW: And finally, this week the Israeli government released data on the efficacy of a fourth dose of the Pfizer vaccine. The study showed a five-fold increase in antibodies a week after the shot. Wow, do we need a fourth shot? I mean, many of us just got our boosters.

ANGELA RASMUSSEN: You know, this really depends on how you want to use vaccines if we want to just keep boosting neutralizing antibody titers, and boosting them and boosting them to make sure that people are as effectively protected against infection altogether as possible, then continuing to boost people is something that would probably work for that. But really, from a larger perspective, we also do need to think about making sure that those precious vaccine doses can get out to other people in the world.

If everybody has the long-term immunity provided by the vaccines, preferably with at least one booster dose, then you’re not going to have as much transmission. You’re not going to have as much prevalence, and you’re not necessarily going to need individual people to have antibody titers that remain extremely high.

IRA FLATOW: Dr. Angela Rasmussen, a virologist at VIDO-InterVac, the University of Saskatchewan’s Vaccine Research Institute in Saskatoon, Saskatchewan. Thank you, again, for taking time to be with us today.

ANGELA RASMUSSEN: Thank you so much, Ira. Take care.

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