Tanya Lewis: Hi, and welcome to COVID, Quickly, a Scientific American podcast series.
Josh Fischman: This is your fast-track update on the COVID pandemic. We bring you up to speed on the science behind the most urgent questions about the virus and the disease. We demystify the research and help you understand what it really means.
Lewis: I’m Tanya Lewis.
Fischman: I’m Josh Fischman.
Lewis: And we’re Scientific American’s senior health editors.
Today, we’ll explain the new official methods to determine if you’re in a pandemic safe zone or danger area…
Fischman: Then we’ll discuss what other pandemics looked like when they were ending—and whether this one, at long last, is heading down a similar path.
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Lewis: The map of the U.S. shifted last week. Or at least the map of COVID danger did. Suddenly a lot of hazardous regions were deemed safer. What happened, Josh? Did COVID disappear?
Fischman: It was a weird moment, Tanya. And no, COVID hasn’t gone away. But last Friday morning people looked at an official Centers for Disease Control map showing much of the nation was in high risk areas. And the next day that map showed about 60 percent of the US was really at low or medium risk. And people in those areas didn’t need to wear a mask.
What happened was three things. One, now we have more tools to keep people safer, such as vaccinations and new antiviral drugs. Two, we are seeing fewer infections as we slide down from the scary Omicron wave. (Though about 2,000 Americans are still dying every day, and none of us should tolerate that level of death.)
And three, because of the first two, the CDC decided to recalculate how it measured COVID risk. That’s what changed the map.
In the old scheme, the agency used only case counts in a particular county. 100 cases or more per 100,000 meant high risk of virus transmission, and the CDC said people in those places should wear masks.
The new scheme shifts the calculation to measures of severe disease. It emphasizes the number of new hospital admissions and how much of a hospital is filled with existing COVID patients. And it still includes case counts. But it ups the levels for high risk to 200 for every 100,000 people.
The agency has a tracker where you can check whether your community is at low, medium or high risk.
Public health experts generally applauded the move. People can usually deal with mild illness. But getting sick enough for an emergency trip to the hospital is what everyone wants to avoid. Also we need to stop overwhelming the health care system with COVID patients.
Case counts rise ahead of hospitalizations, so keeping them in the mix provides communities with early warnings.
If a community rises to high risk, the new guidelines explain how to dial up protection measures, says Katelyn Jetelina, an epidemiologist at the University of Texas Health Science Center in Houston. Masks should go back on, and people should stay out of buildings with poor ventilation, and there should be a push for more vaccinations and booster shots. When the warning indicators drop, measures can be dialed back down.
However, Jetelina is unhappy about the 200 cases allowed before a community moves to high risk. With people getting long COVID, and only about a quarter of children aged 5 through 11 fully vaccinated, she thinks this level of transmission is still unsafe.
And if more people go without masks, with even a moderate transmission rate in their area, it endangers people with weakened immune systems.
But the US wants to push towards pre-pandemic normal, and government policies are following that line. This week the White House announced a series of plans for getting there while COVID stays around. There will be “test and treat” facilities at local pharmacies and community centers, where people can get rapid tests and antiviral medications.
The government wants to step up surveillance for new waves with expanded wastewater testing sites – virus surges can be spotted this way. It also plans to look more aggressively for new variants, with more genetic testing facilities.
J: What’s up to each of us, it now seems, is how to respond when one of these early warning flags goes up. And they will: the virus is now a part of our world. Will we dial up protections such as masks and boosters to stop the spread?
That’s clearly the response that government policymakers are banking on. And people did that early in the pandemic. But going back to more restricted lives may not sit well with Americans today.
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Fischman: Speaking of getting back to normal, you interviewed some historians about how pandemics end. What can we learn from previous pandemics about the end game for COVID?
Lewis: It’s a fascinating question. I talked to John Barry, the historian and author of “The Great Influenza: The story of the deadliest pandemic in history.” The book is an exhaustively reported history of the 1918 influenza, which is believed to have killed at least 50 million people worldwide, and nearly 700,000 in the U.S. alone.
I asked Barry how he would define the end of a pandemic, and he said, basically, the point at which people stop paying attention to it. That seems to be happening already in many places. There is also a scientific component to it—when the virus is causing less severe disease, and when there is ready access to vaccines and therapeutics.
For COVID, we’re almost at that point, Barry says, but we don’t yet have widespread availability of treatments like Pfizer’s antiviral, Paxlovid. Ultimately, though, the end of a pandemic is more of a human decision than a biological one. “We’ve clearly wearied as a society,” Barry told me. But there’s a danger in dropping all precautions too early.
Most histories of the 1918 pandemic describe it as having three waves: in the spring of 1918, the fall of 1918, and the winter and spring of 1919, finally subsiding in the summer of that year. But in fact, a new flu variant emerged in 1920 that caused a fourth wave that was in some places worse than previous waves, Barry says.
Most of the U.S. put in place restrictions during the second wave, and some did for the third. But by the fourth peak in 1920, no cities imposed restrictions. Americans had moved on.
Eventually the disease became milder, in part because most people had some immunity to it from infection, but also because it lost the ability to infect cells in the lungs. There is no law of nature that says a virus has to evolve to be less virulent, Barry says. But over time, our immune systems exerted pressure on the virus to make it harder to infect the lungs—similar to what we are seeing with the Omicron variant.
Right now, Barry is optimistic. COVID cases have fallen dramatically, and most people have some immunity from vaccination, infection, or both. But that doesn’t mean every variant will be mild. There were severe upticks in the flu death toll well after the 1918 pandemic, such as in 1928. Viral evolution is random, so we shouldn’t let down our guard just yet, Barry says.
Ultimately, it won’t be the VIRUS that decides when this pandemic is over. It will be US.
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Lewis: Now you’re up to speed. Thanks for joining us. Our show is edited by the inimitable Jeff DelViscio.
Fischman: Come back in two weeks for the next episode of COVID, Quickly! And check out SciAm.com for updated and in-depth COVID news.
[The above text is a transcript of this podcast.]