At the start of the pandemic, researchers and wearable makers scrambled to see if smartwatches and fitness trackers could detect covid-19. It is now 2023 and while wearables show promise in detecting disease, not too much progress has been made on the covid front. But even as most people move on with their lives, some wearable device makers are still sifting through the data to see what can be learned from the past three years. Case in point: Smart ring maker Oura just released a new study that found significant changes in its users’ biometrics up to 2.5 days before and 10 days after users reported a covid-19 infection.

The study, which was published in the peer-reviewed journal Digital biomarkers, looked at 838 Oura members who had self-reported covid-19 infections and 20,267 members who had received a covid vaccine. It compared temperature, resting heart rate, heart rate variability, respiratory rate and sleep efficiency in the month before and after a vaccination or infection. It also compared physiological responses between variants, age groups and vaccination status.

The findings virtually confirm the existing literature when it comes to covid-19 detection. For example, the physical response to the delta variants was much stronger than with previous variants. Meanwhile, vaccination caused a similar but less severe reaction than an actual infection, which lasted up to four days after the injection. In a similar vein, vaccinated users showed a less severe reaction than unvaccinated users. The response was also found to be greater in users younger than 35 years old than in users older than 50 years old.

“We were somewhat surprised to see responses in all of the biometrics we looked at,” Oura, head of data science Hal Tily, told me. The edge. Tily further noted that in this particular study, Oura was able to document the course of the infection in greater detail than before. For example, Tily said that while temperature differences tended to return to baseline after about 10 days, changes in respiration rate and heart rate could persist for as long as 20 days. While this cannot be taken as evidence of long-term covid, it does suggest that it takes some people longer to return to their biometric baselines after infection.

“On average, we could see symptoms quite clearly extending for days, if not weeks, and in some cases as long as a month after infection,” Tily said.

However, this study has its limitations. It may have been published in a peer-reviewed journal, but that doesn’t make it a clinical trial.

For starters, it didn’t recruit volunteers and it wasn’t a double-blind, randomized trial, which is the gold standard in clinical research. According to Tily, the data, consistent with his data, comes from existing Oura users terms of use And privacy policy, which gives Oura the ability to use anonymized, aggregated data to develop new features or for research. The company also identified which users had received covid or vaccinations based on self-reported tags that users can use to add context to data from a given day.

Because Oura only looked at aggregated averages for the data, Tily said users didn’t have to sign up, as a more rigorous study with individualized data would, like the study Oura did with the University of California San Francisco on temperature and covid-19. (Working with accumulated anonymized user data is a common practice among wearable companies. If you are an Oura user and that scares you, Oura allows you to obtain and delete your own data under its privacy policy.)

Tily admitted these limitations when asked The edgeexplaining that the purpose of the study was not to make any sort of diagnosis, draw definitive conclusions, or even pass FDA regulations.

“My real hope is that we get more people excited about the opportunity to use commercial wearable data to monitor disease at scale,” said Tily, noting that the benefit of wearables for consumers is the sheer amount of data they generate , which can be useful in identifying large-scale trends. For example, rather than focusing on alerting individuals that they may get sick, consumer wearables may be more useful in passively monitoring potential outbreaks in a particular region to inform public health policy.

Not everyone in the scientific community is thrilled about that, however trust data from commercial devices. Compared to consumer technology, medical devices undergo stricter levels of calibration, sanitization and data privacy. Consumer wearables are also more limited by their user base. In this case, Oura’s dataset may not accurately reflect certain ethnic or socioeconomic groups simply because it’s a niche device that appeals to self-quantizing nerds who can afford a $300 device with a $6 monthly subscription.

But even if scientists fully came on board, I wouldn’t hold my breath at the possibility that consumer wearables could soon predict disease. Studies like this show that wearables can detect physiological changes after infection, but the next step is to find out if these devices can tell flu from covid. After that, there are a host of other factors to consider, such as clinical validation, the regulatory process, and whether this is something that will be limited to specific wearable ecosystems.

Essentially, the purpose of this kind of research is not to figure out how to deal with covid-19 as we know it. It is possible to get a flying start on the next one pandemic.

Photography by Victoria Song / The Verge