On March 20, 2020—three days before the first UK lockdown—Tim Spector realized that the country was in desperate need of a Covid tracking app. Spector, a professor of genetic epidemiology at King’s College London, was in an unusually good position to launch exactly that kind of app. He was one of the cofounders of Zoe, a personalized nutrition startup that had just developed a diet-tracking app where people could report what they’d been eating over the past two weeks and receive a personalized food health score.

The diet-tracking app was still in beta testing, but Spector figured that asking people to report their Covid-19 symptoms wasn’t too different from getting them to report their meals. Armed with daily symptom information, the Zoe team could help pinpoint new outbreaks at a time when Covid-19 tests were in extremely limited supply. After five days of frantic development, the Covid Symptom Tracker was live. Within another 10 days it had 2 million downloads. Over the pandemic, some 4.7 million people downloaded the app to report their test results and whether they had Covid-19 symptoms or not.

“It was a leap of faith,” says Spector. At its peak, 2.4 million people tracked their symptoms using the Covid Symptom Tracker. It was one of three surveillance studies the UK government used to track and respond to new outbreaks. Data from the tracker led to the UK government adding loss of smell and taste to the official list of Covid-19 symptoms. Between August 2020 and March 2022, the app was funded with £5.1 million ($6.2 million) from the Department of Health and Social Care.

But in early May 2022, Zoe announced in an email to users that its Covid tracking app would no longer be just a place for people to report their Covid symptoms. The Covid Symptom Tracker was becoming the Zoe Health Study, which asks people to take 10 seconds a day to log their mental and physical health beyond Covid. People who agree to take part in this wider study are asked to establish their baseline health—reporting everything from hair loss to mouth ulcers—as well as providing daily health updates. The company says this data will be used to “fight the most important health issues of our time,” but that it might also be used to develop commercial health, nutrition, and lifestyle products. (Zoe also sells nutrition tests and subscriptions to a personalized nutrition platform.)

Zoe isn’t the only Covid app developer pivoting away from the pandemic. In Berlin, a contact-tracing app called Luca is reinventing itself as a payment system, while in northern Italy an app set up to track coronavirus cases now warns citizens about natural disasters. With the most urgent phase of the pandemic now over, developers are looking for ways to squeeze more value out of the users who have downloaded their apps. The great Covid-19 data pivot is well and truly underway.

Switching to broader health tracking wasn’t Spector’s first choice for the Zoe Covid Symptom Tracker. His original plan was to use the app to track other respiratory diseases, or infectious diseases like monkeypox. But in March 2022 the Department of Health and Social Care halted funding for the app, which sent Spector and his colleagues at Zoe looking for other options.

Spector sees this current version of the Zoe app as a giant citizen science project. Users can sign up to different studies, which involve answering questions through the app. Current studies include investigations into the gut microbiome, early signs of dementia, and the role of immune health in heart disease. Before the pandemic, recruiting hundreds of thousands of people for a study would be nearly impossible, but the Zoe app is now a huge potential resource for new research. “I’d love to see what happens when 100,000 people skip breakfast for two weeks,” says Spector.

People who reported Covid symptoms aren’t automatically included in these new studies. Some 800,000 people have agreed to track their health beyond Covid through the Zoe app, while a smaller proportion of people have signed up to specific trials. But it’s hard to imagine these huge sign-up figures without the app having played such a prominent role during the pandemic.

“These emergency situations become catalysts and create a very unique environment,” says Angeliki Kerasidou, an ethics professor at the University of Oxford. “Something we need to be thinking a bit more carefully about is how we use these situations and what we do with them.”

There’s also a question about the line between providing care and conducting research, Kerasidou says. At the height of the pandemic, the National Health Services of Wales and Scotland directed people to track their symptoms through the Zoe app. Tracking Covid symptoms that way might have seemed like the socially responsible thing to do, but now that the app’s emphasis is on wider health tracking and clinical studies, should people feel the same obligation to take part?

The German app Luca is undergoing an even more dramatic about-face. In spring 2021, 13 German states had signed contact-tracing contracts with the app, worth a total of €21.3 million ($22.4 million). Back then, people would use the app to check into restaurants or other businesses by scanning a QR code. If they crossed paths with someone who shortly afterward tested positive for the virus, the app would tell them to isolate.

But as Germany’s vaccination rates improved, state contracts began to evaporate. In response, Luca’s CEO, Patrick Hennig, looked around for a new business model. In February 2022, Luca revealed it would transform into a payments app, with its new payments function launching in early June.

This was a bold business decision in notoriously cash-friendly Germany. Around 46 percent of Germans still prefer to use cash, according to a 2021 study by British polling company YouGov, compared to just over 20 percent in the UK. But Hennig is hoping to change entrenched habits by leveraging the Luca brand—and user base of 40 million registered people—that the company has built throughout the pandemic.

The idea is that people can use Luca as an alternative to card terminals. At the end of a meal, restaurant-goers scan a QR code that shows them their bill and enables them to pay through the Luca app, using either Apple Pay or their card details. Hennig is attempting to incentivize restaurants to use his system by undercutting the 1–3 percent fee they’re usually charged for using a card terminal. Right now, Luca is free for restaurants and shops to use, but that will shift to a 0.5 percent fee at the end of the year, Hennig says. Over 1,000 restaurants and shops have signed up so far.

“We definitely have an advantage that all the restaurants relate Luca to a system that saved them a lot of time during corona,” Hennig says. Investors seem to agree. The company raised €30 million back in April. “It was easy,” says Hennig, explaining that it only took a few days to raise the cash.

But controversy has followed Luca since its inception. IT experts have criticized the app’s security. In April 2021, researchers Bianca Kastl and Tobias Ravenstein uncovered a security gap with Luca’s key fobs—small tags that people could use to check in to restaurants if they didn’t own a smartphone. Kastl and Ravenstein demonstrated how they could use the QR code printed on the key fob to access a person’s check-in history. At the time, Luca said it had deactivated this option “immediately.”

Then, when a man died outside a restaurant in November 2021, in the west German city of Mainz, the local health department used the Luca app to access the contact details of 21 potential witnesses who were nearby at the time and handed these over to police—causing an uproar.

Hennig has denied that either case represented a flaw in the app’s security. In Mainz, he says the health department simulated a Covid-19 case in the restaurant in order to trace who was nearby at the time, while he describes the key fob issue as a problem with the key, not Luca. “This was also no data breach, as someone has to steal the key from the respective person,” he says.

As part of its pivot, the company behind Luca has tried to head off privacy concerns—announcing in May that it had deleted all user data collected during the pandemic. But such concerns have stuck to the company’s reputation, according to Kastl, one of the IT experts who investigated Luca’s key fobs. “If they weren’t really good at keeping contact-tracing data safe, why would they be really good at keeping financial data safe?”

Hennig, though, denies Luca will store personal payment data and says the app has always protected people’s information. “Luca always kept the data safe and secure,” he says.

Phil Booth, coordinator at activist group MedConfidential, says it was inevitable that businesses and projects that provided services through the pandemic would try to parlay that prominence into post-pandemic success. “Everyone’s seeing that there is opportunity here,” he says. But government-backed apps can also blur the line between public health and private profit. “The NHS is chronically commercially naive,” he says, pointing to the example of Evergreen Life—an app that lets people in the UK book appointments with doctors and organize prescriptions but also sells private DNA tests. Booth calls for clearer signposting about how people’s data is used in all of these situations and says that the purpose for data collection should be made clear at the very beginning of each project.

Spector points out that when it comes to the Zoe app, users have to give fresh consent if they choose to become part of the wider health study or specific clinical trials. He also says that Zoe would never have been so popular, or been developed so quickly, if the project had been left to academia or the government. But Spector says the kind of vast citizen science project that he hopes Zoe will become was impossible to predict before the pandemic. “It was a once in a lifetime opportunity,” he says. “It’s shown that if people are given the right tools, they’re very happy to engage with science.”