Faye Flam

How to Solve the Covid Testing Data Problem

For the first time, we’re heading into a Covid winter mostly free of restrictions. People are tired of mandates and rules, tired of lining up for tests and even, as booster rates show, tired of getting shots. And so public health needs a new approach to do any good — one based not on restrictions and mandates and more on providing useful tools and information.

It’s not just fatigue that’s setting in, but something else — we’re no longer being advised to hold off on normal life for just a few more months, as many did until vaccines, until delta subsided, until the first and second omicron waves receded. At a recent symposium hosted by Harvard Medical School, biologists tracking the Covid pandemic forecast a long purgatory — the situation is much better than in 2020, but there’s no end in sight for the stream of new variants that keep evolving ways to evade immunity.

The only good news here is that technology is advancing, and people aren’t tired of adopting innovations. One of the best technologies for helping us assess local risk is sewage analysis. It’s emerged as the fastest and most reliable source of information about the surges and lulls in the pandemic, as well as which variants are taking over in which regions.

Popular sites for tracking the pandemic such the New York Times Covid tracker have become less useful because they rely on PCR testing; most infected people, if they do test, are using antigen tests at home and not reporting the results.

Perhaps a better source now is produced by the sewage data company Biobot: biobot.io/data. The company was founded by computational biologist Mariana Matus and urban studies researcher Newsha Ghaeli, who started thinking about the wealth of information in wastewater while they were colleagues at MIT. Right now, the site shows cases levelling off or falling in most of the country, but with rising surges in a few places in the Northeast.

In a Zoom interview, Ghaeli walked me through the site, and showed me how they’re making wastewater measurements all over the country. The wastewater numbers initially followed the same pattern as test results, though they rose and fell a week or so earlier, since it can take days for an infected person to get a test and for the results to come back. But earlier this year, as testing dropped off, the wastewater measurements separated — showing new hills that weren’t visible from official testing data.

While data based on testing is skewed by the availability and popularity of PCR tests, wastewater numbers can give us a less skewed picture of regional risks. The wastewater analysis includes adjustments for the population density, Ghaeli said, to estimate how prevalent the virus is per capita.

That kind of data gives Covid-cautious people the information they need to reduce their risk. “It’s akin to looking at weather data, and just making a quick decision as to do I bring an umbrella with me when I’m going out today,” says Ghaeli. “For me, it’s like, do I wear a mask on the subway today?” she said.

While Biobot has done an impressive job on its own, more data would make such tools even better. A uniform, nationwide system would better help us track Covid’s prevalence and the ever-more complex array of variants that keep emerging, says Sam Scarpino, vice president of pathogen surveillance for the Rockefeller Foundation.

It would also be a public health service to make sure that the data is presented simply and clearly, so that people can check it as effortlessly as they do the weather forecast. And just as with the weather, regular “Covid forecasts” should be featured on the local news — especially when a disaster is on the way.

This kind of data can be a great help to the 57% of people who are still “at least somewhat concerned” about Covid, according to an Axios-Ipsos poll. Most people aren’t in denial that there’s a continued pandemic, but we’re also not planning to give up socializing or restaurants indefinitely. Better wastewater data is a tool that can let more people responsibly calibrate the risk in their neighborhood, but it isn’t free — it requires more funding.

One of the doctors at the Harvard meeting, Jacob Lemieux, told me in a subsequent conversation that he worries it’s not just the public but Congress that’s getting pandemic fatigue. That’s bad for us all because Covid remains a major killer, and we need better vaccines, a better understanding of long Covid, continued access to home test kits, and of course funding for wastewater monitoring. Wastewater data is our best hope for keeping informed, and might even tip us off to the next pandemic.