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Possible spring COVID surge? Mayo infectious disease expert shares insights

Two people wearing face masks stand under an umbrella.
Peter Vang and Tanaya Walker Vang of Shoreview take shelter from the rain May 17, 2020 after shopping at the St. Paul Farmers' Market.
Christine T. Nguyen | MPR News 2020

When you look around, it would appear that many people think the pandemic is over. Hospitalizations and deaths in Minnesota are at some of their lowest levels of the pandemic. But there's been a fast rise in cases on the East Coast.

Testing of sewage in the Twin Cities also finds a rising load of the BA.2 subvariant. Dr. Gregory Poland, an infectious disease expert at Mayo Clinic and founder of Mayo's Vaccine Research Group, recently joined us to share his insights on what could be next for Minnesota.

The following transcript has been lightly edited for length and clarity.

What factors are pointing to a potential surge in cases here in our region?

Number one, most of America — and as I walk around the streets of Rochester — people are pretending that the pandemic is over. That's a deadly and wrong assumption.

The second is that our immunity does wane with time. The third is that this is a highly transmissible variant. The most transmissible SARS-CoV-2 viral variant we have seen. In fact, it is just below the level of contagiousness that measles viruses — which is singularly the most transmissible human virus that we know about.

And then lastly, as you mentioned, every indicator that we can look at shows a steady uptick in cases. Wastewater viral loads are elevated. If you look at Philadelphia, they've had a 70 percent increase in new cases over the last 10 days. New York, New Jersey, just under 70 percent increase. So this is not good news.

You mentioned that this is a very transmissible variant, but how likely is someone to get really sick from it?

If they are vaccinated, they are very highly likely to be protected against death, hospitalization, having to go on a ventilator. If they are not fully vaccinated, then all odds are off and the risks increase. Now, we do think that the virulence, the disease causing ability of this variant is less for example than delta was, but less doesn't mean zero.

You know, 69 percent of Minnesotans are fully vaccinated. What does the vaccination rate and the booster uptake need to be?

You’re really kind of driving at this idea of herd immunity, and with a virus this contagious you probably need to be in the low to mid 90 percentile, not the 70 and 80 percent, that people who have not studied this virus, you know, keep proposing. It's clear that it's closer to what measles herd immunity needs to be.

So really, we are in a sense, prolonging the pandemic and allowing the other variants to to grow and to bubble up. Is that right?

That's exactly right. The way I put it to the media is we've watched this movie five times with the same ending. It is magical thinking to believe that somehow this one's going to be different.

In fact, if you look at most forecasts — and they're just that, forecast — the expectation is that we will very likely see a surge this fall as antibody levels further wane as people have COVID fatigue, as they disregard masking. You know, the number of people that have actually gone and gotten the first booster, much less the possibility of a second booster, is really surprisingly low. If you look at Minnesota's population that's up to date — that means their primary series, plus one booster — if you look at the entire population, it's less than 50 percent.

Should people then wait to get boosted, maybe even a second time if you're thinking about a surge in the fall?

This is a really difficult question because we know that with that booster, your antibody levels shoot up, but they're probably only at that elevated level of protection for somewhere around eight to 12 weeks.

And so the ideal time to get your booster would be two weeks before you're exposed, but when are you going to be exposed? So I would say if you're going to travel, if you're going to be in a high risk situation, if you're somebody who doesn't wear a proper mask, probably go get your booster.

Now, if you're somebody who's very careful and thoughtful about this, who wears the proper mask properly, who's not dining indoors, taking those levels of precaution? You could watch the data carefully and hold right now. Now if you're immunocompromised, elderly or have a lot of other medical problems, I wouldn't advise waiting.

Do you think we might see a surge here this spring?

I don't know if we'll see one this spring. My guess is that it will require antibody levels to fall further, for people to further be lulled into thinking the pandemic is over. And probably more like summer or beginning of school this fall.