A doctor answers questions on COVID tests, future variants and more

A person waits to be tested for COVID-19
A person waits to be tested for COVID-19 in Johannesburg, South Africa.
Jerome Delay | AP 2021

Omicron appears to be beating a retreat in parts of the country. But in Minnesota, it's tough to tell. In Wednesday's state health department update, 80 percent of newly reported COVID-19 cases were from tests taken more than a week ago.

Infectious disease experts at Mayo Clinic say there are some hopeful signs that the omicron surge in Minnesota may be peaking soon. But many hospitals are still coping with a crushing number of patients, as hospitalizations and deaths often trail infections by a couple of weeks.

Joining host Cathy Wurzer to answer some questions about the ongoing pandemic surge was Dr. Melanie Swift, co-chair of Mayo Clinic's COVID-19 Vaccine Allocation and Distribution Work Group. Swift is an occupational medicine physician and internist, with a special interest in the health and well-being of health care professionals.

The following is a transcript of the interview, lightly edited for clarity. Listen to the full conversation with the audio player above.

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Metro area hospitals are at record-high levels of COVID-19 patients. What are you seeing at Mayo?

We're seeing the same trends here. Hospitalization does tend to trail the initial infection by a couple of weeks, and so we are starting to see the omicron surge hit our hospitals now. We are at record capacity for COVID cases.

Some models indicate 50,000 to as many as 300,000 more Americans could die of COVID-19 before this surge ebbs. Yet some describe omicron as being mild. Does that lull people into thinking it's going to be OK?

This is the difference between your individual risk and our population risk. Omicron, for an individual person, does tend to cause a milder disease, particularly if that person's vaccinated and especially if they're boosted.

It's just so highly transmissible. It has such a high “attack rate” — which is, of the people exposed, how many of them get the infection — that the absolute numbers drive a higher number of hospitalizations. It's simple math. We have many, many more people being infected. So even though the percent[age] of those getting really sick is lower, the absolute number of sick people is going up.

Are people with comorbidities at special risk, even if they're vaxxed and boosted?

They are. Those conditions — also pregnancy — continue to be indicators of increased risk. Those are people that we're trying to identify for early treatment to try to keep them out of the hospital. It's definitely still a worry. We're still learning about omicron as we go, but those populations are at risk of a harder punch, so to speak.

Are vaccinated children ages 5 to 11 experiencing breakthrough COVID cases?

I think it's a little too soon to have clear numbers for that. What we are seeing in the hospital is that the majority of hospitalized cases are unvaccinated in all age groups — or not boosted for those age groups that are eligible to be boosted. The only boosted folks we tend to see in the hospital are those that have underlying immunosuppression.

If everyone gets vaccinated, will the virus stop mutating?

Vaccination does a couple of things. It does protect against the severity of infection. So even though we are seeing people who are vaccinated have breakthrough infections — and even some people who are boosted — the severity of that infection is much lower.

It's similar to the flu shot. Flu vaccination doesn't necessarily prevent you from getting influenza, but you're much less likely to go [to] the hospital [with] it or die of it. So that's one argument for vaccination. And that's at the individual risk level.

But when you think about the population — if we can increase our vaccination levels, it does interrupt transmission of more and more variants. And that can help us prevent and forestall having new variants emerge that would be as big a problem as omicron, or potentially worse.

How can you treat COVID at home when you're pregnant?

Most people who develop COVID actually can provide self-care at home: rest, hydration, some acetaminophen or Tylenol as needed for symptoms. For people who are at extremely high risk of being hospitalized — like those who are on cancer chemotherapy or are severely immunosuppressed — those are people who may be eligible for a treatment, early in the course of their infection, with either an antiviral or a monoclonal antibody, to keep them from being in the hospital.

But most people don't need those. Most people can just essentially do the same kinds of things you do for the flu at home. There aren't any known herbal [remedies] or supplements that are effective [treatments for COVID-19].

What do you know about the monoclonal antibody treatment for people who are pregnant?

Monoclonal antibodies can be used in pregnancy. If the person is high risk, we know monoclonal antibodies do potentially also provide some protection to the fetus. So it's not a contraindication.

There's only one monoclonal antibody that currently works against omicron, so there's less of it available. We have stopped, by and large, administering the other monoclonal antibodies because right now, all we're having is omicron [cases], and the others are not effective against that.

Which is the best COVID test to use?

It's gotten really complex. And now with the rollout of all the antigen kits from the government program and private employers, insurance programs, etcetera, it's getting messy pretty fast.

So here's the difference. The PCR test that's done in a laboratory is extremely sensitive, exquisitely sensitive, and can detect an early COVID infection before symptoms even develop. The downside of it is that once you've had COVID, [you can continue to test positive on a] PCR test for weeks, even though you're no longer contagious.

The antigen tests that people can now do at home, much like a home pregnancy test — you do it in your own home and get your results within about 15 minutes. They are less sensitive, so you could have a very early infection, not yet detectable by one of those kits, and [the test] could be negative.

However, [antigen tests are] still very useful. So times that we would use those are: If someone is having symptoms and they don't have ready access to fast turnaround [on] a PCR test, or they have barriers to getting a PCR test, and they've got a home antigen test. You can go ahead and do that antigen test for those symptoms.

And if it's positive, you don't need to repeat it. If it's positive and you've got symptoms, that's enough for us to say you've got COVID. Now, if it's negative and you continue to have symptoms, then you do need to get a PCR test, because [the antigen test] might have missed it.

The other time that we're using [antigen tests], especially for health care workers, is determining when someone could come out of isolation early after they've had a COVID infection. We don't have a perfect test to show that you're no longer contagious. But the antigen test clears much quicker than the PCR test after an infection.

It's our best proxy for, “Is this person still contagious?” As I said, it's not 100 percent. But if you have completed at least your five days of isolation and you have a negative antigen test, we feel much better that you're not contagious and could come back into, say, the workplace, while still wearing a mask for your full 10 days.

If you need [testing] for some non-symptomatic purpose, it's usually better to get a PCR test.

What are you seeing when it comes to long COVID symptoms in patients who've been vaccinated and boosted?

I think it's too early to really say. Long COVID is a condition that doesn't have a hard-and-fast timeframe, but we look for people to be symptomatic for at least 10 or 12 weeks after their initial COVID infection to say, OK, you've got long COVID.

We just haven't had enough time yet. And I think omicron may change that game as well because we are seeing milder cases, by and large. So we don't really know how much long COVID we're going to get, either in the boosted population or among people who got an omicron infection.

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