Two COVID maps released and kept updated by the CDC. The map on the left reflects new metrics for monitoring the burden of COVID, with most counties in either the low or medium category. The map on the right reflects current COVID transmission levels, with the majority of counties at either substantial or high transmission. NPR/Centers for Disease Control hide caption
NPR/Centers for Disease Control
Two COVID maps released and kept updated by the CDC. The map on the left reflects new metrics for monitoring the burden of COVID, with most counties in either the low or medium category. The map on the right reflects current COVID transmission levels, with the majority of counties at either substantial or high transmission.
NPR/Centers for Disease Control
Cindy Watson would like some clarity from the Centers for Disease Control and Prevention.
Madison County, Iowa, where she lives, is categorized as having “low” COVID levels on the agency’s new lookup tool for COVID-19 Community Levels – it’s even colored an inviting green on the map. But when she looked at the agency’s existing map of COVID transmission levels, the same county – and much of the country – was bright red and classified as “high.”
In fact, Watson was among the millions of Americans who were instantly transported to a green zone in late February, when the agency unveiled its new metrics and map. That color change wasn’t simply symbolic. It came with new guidance that said Watson — and anyone else living somewhere green or yellow — could stop wearing masks in public.
Watson wonders – what changed? Can she trust the new map? She is vaccinated and boosted, but she wants to protect loved ones, like her mother-in-law.
“Is it OK to go out unmasked and then go and see her?” she asks. She teaches math and science at a community college and describes herself as a data-driven person. “If I’m confused, holy cow, everybody else has got to be really confused by it all,” she says.
Up until late February, the CDC based its rankings of a county’s level of risk on the amount of virus spreading there and what portion of lab tests were found to be positive. The new framework instead focuses on the situation in hospitals — how many people are being admitted for COVID-19 and how much capacity is left.
Critics of CDC’s new approach say the agency seems to have moved the goalposts to justify the political imperative to let people get back to their normal lives.
“What it looks like is quite literally a changing of thresholds in order to justify a policy that I think assumes way too much risk,” says Jessica Malaty Rivera, an epidemiologist at the Pandemic Prevention Institute.
Experts in public health and infectious disease NPR interviewed say that for the average American trying to decide on behaviors like going to restaurants, the CDC’s new blueprint for navigating the pandemic leave them with an incomplete picture of their individual risk.
It also moves the U.S. away from collective response where members of a community join together in shared precautions, instead leaving vulnerable people to fend for themselves.
The debate over how to measure a given county’s COVID-19 level may seem academic, given that cases are in dramatic decline across the U.S. But the question is what the metrics will mean for how well communities predict and avert future surges — and how much life is lost.
A shift toward individual responsibility
The rationale behind the CDC’s new formula is that hospital capacity serves as a signal for how bad a local outbreak is.
“We want to prevent hospitalizations, we want to prevent our hospitals from becoming overwhelmed – so our metrics were really [developed] with that in mind,” CDC director Rochelle Walensky said while presenting the new map last month.
The CDC’s COVID-19 Community Levels map is updated weekly on the agency’s web site. CDC hide caption
The CDC’s new metrics for assessing community COVID levels focus heavily on hospital admissions and capacity. Centers for Disease Control hide caption
Centers for Disease Control
The CDC’s new metrics for assessing community COVID levels focus heavily on hospital admissions and capacity.
Centers for Disease Control
The red, yellow and green COVID-19 levels are based on two key metrics: hospital admissions and overall hospital capacity. A county’s COVID level is “low” if new hospital admissions are fewer than 10 out of every 100,000 people or fewer than 10% of hospital beds are filled with COVID-19 patients — whichever number is highest. It’s medium or high when hospitalizations are above that level.
These new categories might help local policymakers worrying about hospitals getting overwhelmed, but it is not very useful for individuals trying to avoid getting a COVID infection when they go to the gym or the grocery, says Dr. Jeff Duchin, public health officer for Seattle and King County in Washington state.
“It’s not as simple as, ‘What color is it?’ ” Duchin says. “There’s a spectrum of risk, particularly within the low risk category and there are many situations where individuals would not be comfortable accepting that risk without taking additional precautions,” such as social distancing, wearing a mask, and avoiding crowded indoor situations.
Of special concern is how the CDC has defined its low risk “green” category. Previously a county reached “low transmission” when there were under 10 new weekly cases per 100,000. The new “low” level does take cases into account, but has raised the threshold substantially. According to the new map, as long as hospital metrics are low, a county is green with any number up to 200 weekly cases per 100,000 people.
“It’s extraordinarily high,” says Malaty Rivera. “Everybody that I know in the infectious disease space is kind of gobsmacked by that shift.”
CDC did not make anyone available for an interview for this story, but a technical brief explains how agency staff ran analyses of historical data to find the levels that most reliably predicted a surge in cases. The agency says its new COVID-19 community levels provide a sizable improvement in predicting local outbreaks three weeks into the future over their previous method of identifying risk levels.
There’s an argument for moving away from case counts if the goal is protecting hospitals: More people are relying on rapid at-home tests, making official numbers often undercounts, and a smaller share of omicron cases have led to hospitalizations compared to earlier variants, largely because of vaccines and immunity from prior infections.
In its guidance, CDC does note that some people may want to be more cautious, including those who are immunocompromised or at high risk of severe disease; they’re advised to talk to their doctor about wearing a facemask or getting treatment, even if the risk level is “low” or “medium” where they live.
But this approach seems to abandon a fundamental goal of public health — to keep everyone safe through collective action, says Jason Salemi, an epidemiologist at the University of South Florida College of Public Health. Even with cases declining, he says, many people are still at high risk of severe disease, including the immunocompromised, unvaccinated kids and the elderly.
“They’re shifting from a community-wide response to really putting the onus on individuals and particularly individuals who have already borne the disproportionate burden of this pandemic,” he says.
Hospital doctors and nurses treat COVID-19 patients in a makeshift ICU wing at Harbor UCLA Medical Center in late 2020. During big surges, hospitals around the U.S. have often been overwhelmed, while communities struggle to get an outbreak under control. Dania Maxwell / Los Angeles Times via Getty Images hide caption
Dania Maxwell / Los Angeles Times via Getty Images
Hospital doctors and nurses treat COVID-19 patients in a makeshift ICU wing at Harbor UCLA Medical Center in late 2020. During big surges, hospitals around the U.S. have often been overwhelmed, while communities struggle to get an outbreak under control.
Dania Maxwell / Los Angeles Times via Getty Images
Relying on a lagging indicator
Some experts do see the new metrics as a sensible shift toward living with the virus – recognizing that many Americans have no tolerance left for mandates and restrictions.
“This is a transition that happens for all public health conditions in some way, a balance between collective responsibility and individual responsibility,” argues Dr. Jay Varma, who directs the Weill Cornell Center for Pandemic Prevention and Response and has advised former New York City Mayor Bill de Blasio. Ultimately, he says, public health decisions are made at the local level, not by federal agencies, he says, so the CDC guidance should “represent the floor, not the ceiling on pandemic prevention.”
And says Alison Buttenheim, an associate professor of health policy and nursing at the University of Pennsylvania, the guidance is easy to take in. “I think the CDC is responding to an appetite from the American public for something very, very simple that allows me to stay as close to my regular or normal life as possible,” she says.
But Malaty Rivera points out the focus on hospitalizations — not case counts — ties a county’s level to what’s considered a “lagging indicator.” It generally takes about a week or more for a rise in cases to show up as a corresponding increase in hospital admissions. This means a substantial amount of disease can spread before a community reaches the highest level of risk, at which point interventions like facemasks are recommended.
“I worry that is opening the door for a lot of transmission that might be prevented if more people were wearing masks, especially if a new variant might arise and there might be an early signal of a new wave,” says Dr. Joshua Salomon, a health policy professor at the Stanford School of Medicine.
In fact, Salomon and a colleague tried to calculate how many people would be expected to die from COVID-19 once a community entered the “high level,” as defined by the new CDC metrics. Their estimate was based on historical data from the delta and omicron surges and assumed that deaths show up in the data about 21 day after infections.
“For most places, mortality was in the neighborhood of about three [deaths] per million people each day,” says Salomon. To put that in perspective: that would equal about a thousand deaths per day nationally, if this was the condition across the entire U.S.
Salomon acknowledges this is “speculative,” in part because it’s impossible to predict whether future variants will inflict the same level of death as earlier ones. Still, he says it raises questions about what level of mortality the CDC is willing to tolerate before sounding the alarm and calling for more public health precautions.
“Once you reach those thresholds, we miss the opportunity to prevent infections that might lead to deaths later – so it is very late in the game,” he says.
Where that leaves individuals
The CDC undertook an exceedingly difficult task when it revamped its guidance: Give the U.S. a simple way of understanding COVID-19 risk.
The truth is no single metric can accomplish that.
Data on testing has its limits — many infections go undetected and rapid at-home tests often don’t make it into the official case counts. Deciding what constitutes “low” versus “high” is far from a perfect science. “These cut-offs are to some degree arbitrary by necessity,” says Duchin.
That said, multiple experts told NPR that one of the most straightforward approaches is to drill down into the number of confirmed new infections per capita in your area. The CDC’s older map (still available here and used to guide precautions in health care settings) requires a county to be at under 50 cases weekly per 100,000 people in order to be considered at “moderate” risk. That’s roughly seven new cases a day on average.
“That is a tolerable threshold,” says Malaty Rivera.
For some infectious disease experts, a rate of 1 to 10 new daily cases per 100,000 people would be low enough for them to feel comfortable taking off their mask, although that, too, depends on the setting (a crowded concert venue and a grocery store are very different things).
A consortium of public health researchers that maps counties by current risk level says more cautious behavior is required when there are 10 or more new daily cases per 100,000.
The positivity rate can also be a valuable guide because it helps indicate whether enough testing is being done to pick up all the cases in a community. A higher rate indicates that there’s probably more virus circulating in your community than reflected in daily case reports. If the positivity rate is hovering at a low level for weeks, that is a good sign. One group of researchers says under 3% is a safe figure.
Vaccinations coverage is also a solid indicator; however, that only tells part of the story. As omicron showed, people who are vaccinated can still spread the virus.
A final metric to consider: what direction are cases heading in your community?
When cases are on their way up, “there’s reason to be more cautious,” says Stanford’s Salomon, especially with a new variant when there’s uncertainty about how contagious and lethal it is.
All of this ultimately becomes a very personal decision, filtered through your own risk tolerance. That depends on a huge mix of factors — be that underlying health conditions, vaccination status, or politics.
“I hope a lesson we can take from all of this is we need to give people tools and comfort and make it apolitical,” says Buttenheim at UPenn. “So that we are capable of flexing up, flexing down and responding to local conditions in a way that doesn’t get everybody’s knickers in a twist.”