The real COVID surge is (much) bigger than it looks. But don’t panic

People walk past a Covid testing site in New York City on May 17. New York Health Commissioner Dr. Ashwin Vasan has moved from a “medium” COVID-19 alert level to a “high” alert level after a spike in cases in all five counties. (Photo by Spencer Platt/Getty Images)

Cases of COVID-19 are – once again – on the rise. In the United States, an average of more than 100,000 new cases are reported across the country each day. That’s nearly twice what it was a month ago and four times what it was this time last year.

And the real number of cases is likely much higher, according to health officials. With many people now relying on at-home testing, “we’re clearly undercounting infections,” said Dr. Ashish Jha, White House COVID-19 Response Coordinator, to reporters at the recent COVID press conference. Hospital admissions are also increasing, albeit gradually in most places.

In most places, however, health officials have not called for new COVID restrictions. How big is the increase really? And is there anything you should do about it?

Measurement of the true number of infections

Official undercounting of cases isn’t exactly a new problem. At the beginning of the pandemic, many cases went undetected because testing was unreliable and supply limited.

“We saw early on — in March 2020 — that maybe one in 10, maybe one in 12 infections actually got caught,” says Jeffrey Shaman, an infectious disease specialist at Columbia University whose lab has been working on the actual number of infection to model.

Very early research efforts to find out how many infections were occurring in the community involved testing a sample of residents for SARS-CoV-2 antibodies. As the pandemic progressed, this method didn’t work as well, Shaman explains, because antibodies waned over time after infection, and vaccinations complicated the antibody picture.

Shaman’s research group turned to using models to estimate the “detection rate” — the proportion of real infections caught in official case counts. This rate has fluctuated – in late 2020 it was estimated that one in four cases was being counted. It was closer to one in six during the Omicron rise.

Given the widespread availability of rapid at-home tests that go unreported to public health officials, Shaman believes the actual number of cases could be eight times the actual case count. In other words, instead of 100,000 new cases per day, the true number could be 800,000 cases per day.

Take that estimate with a huge grain of salt, he advises. It is becoming increasingly difficult to get a firm grip on the current detection rate.

Ellume COVID-19 home tests are seen at a CVS in the Navy Yard neighborhood of Washington, DC, where seniors received free tests covered by Medicare on Monday, April 4. (Photo by Tom Williams/CQ-Roll Call, Inc via Getty Images)

Sewage monitoring sites across the country are reinforcing the notion that the virus is on the rise. More than half of the locations have seen “slight increases” in virus concentrations, according to the CDC, although the system doesn’t cover the whole country and isn’t yet set up to offer people a running estimate of the true number of cases beyond the official counts .

All of this is a predictable consequence of simple, ubiquitous home testing, says Gigi Gronvall, senior scholar at the Johns Hopkins Center for Health Security.

“Having that information at hand for people to get the results they need, so they can act on them immediately — it’s totally worth it,” she says. But it is at the expense of the data, “and one has to conclude that there are more cases than are reported.”

The next climb could be worse

As an epidemiologist, that uncertainty isn’t ideal, says Katelyn Jetelina, an associate professor at the University of Texas Health Science Center who writes the newsletter Your Local Epidemiologist. And even if case numbers are much higher than they seem, this summer may not see a health crisis like previous surges, she says.

As the weather gets warmer and people spend more time outdoors, “transmission is much lower because of outdoor ventilation,” she says. Also, following the massive spike in infections from the Omicron variant, she says, “We just have such a high level of infection-induced immunity that we have a very high immunity wall,” which CDC also estimated. Basically, if someone has had an infection recently, they’re less likely to be infected again, so the virus might not be able to spread as much or make people sick as much.

The country’s current population-level immunity is one of the reasons Maciej Boni, a professor of biology at Penn State’s Center for Infectious Disease Dynamics, says it makes sense for policymakers to hold off on introducing mitigation measures for now.

“The reason is that we will exhaust people’s patience and we may exhaust certain health resources [and] political capital that we want to save for when we really need it,” he says.

He predicts a much more dangerous surge ahead in the fall and winter. Then he thinks that health authorities should start “stepping up the new measures that will probably be needed to reduce the number of cases,” he explains.

Jetelina agrees that the country will not take big steps at the moment. “I don’t see any major policy changes until the virus has another omicron-like event or major mutation,” she says.

Find out what’s happening with the virus where you are

While public health officials may not be sounding the alarm about the rise in cases, health researchers agree that certain people should take note of the fact of the current, sometimes unseen spike: the elderly who haven’t been vaccinated or boosted recently.

“This is the low-hanging fruit here,” says Jetelina. “Just get the vaccine. Go get your booster. Don’t think about it too much.” Nearly a third of people over 65 who are eligible for a booster shot have not received one, according to the CDC’s Vaccine Tracker — despite clear evidence that doing so reduces the risk of hospitalization and death.

People at higher risk should generally be more cautious when cases get high. But with official case count reports from public health officials missing so much data, how do you figure out how bad COVID transmission is in your community?

Just as you might watch the weather forecaster on TV when a storm is forecast, but also step outside to look at the sky, public health experts say it’s wise to brace yourself for both official and anecdotal signals of rising cases .

Keep an eye on case counts (since you know they only capture a fraction of the true cases out there) and hospitalizations, and listen to public health officials. But also keep an eye out for text messages from friends and colleagues telling you they have contracted COVID-19.

“This anecdotal evidence could also be helpful in decision-making,” says Jetelina. If there seems to be a sudden spike, you know there are more viruses circulating where you live.

Another signal to look out for: If your workplace or children’s school conducts surveillance testing — which is regular testing of everyone, including people who are not showing symptoms — it can be very helpful in staying up to date on what’s happening happened to the virus on site.

“Where I am in Miami-Dade County, there are still city employees who may need to be tested regularly, and we may be getting an underlying signal as to when we have a spike,” says University of UC epidemiologist Zinzi Bailey Miami.

Bailey also likes to use COVID-19 hospitalization data as a proxy for what’s happening in her community.

“I’m looking at my local hospitalizations and when they start ticking upwards I’ll change my behavior accordingly – I’ll pay a little more attention to masking, I’ll pay a little more attention to what indoor spaces I’m in.” stop and how often I’m going to do that,” she says.

Jetelina uses trend lines in case counts to make decisions for her own family. “My ears are starting to perk up [when there’s] just over 50-75% increase in the last two weeks,” she says. Looking at downtrend lines, if the line is “just starting to slowly creep up, that’s fine, but if the acceleration is accelerating, then something seems amiss to me.”

Then grab a raincoat in case of bad weather – i.e. your vaccination protection or get a boost if you are not up to date. While it’s easy to make an appointment at a pharmacy, fewer than half of Americans who received their first vaccines still haven’t received the first booster, which was approved in the fall. And now there’s a second booster for everyone over 50.

Beyond vaccination, if the virus is currently spreading heavily in your community, anyone at high risk because of their age or underlying medical conditions — or living with someone who is — would be wise to take their personal COVID-19 precautions to meet: Be selective about time to be indoors in public spaces while wearing a quality, well-fitting mask.

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