After seeing Twitter threads pointing out a potential link between negative candle reviews and spikes in COVID cases, one professor sought to determine if there was a relationship between the two.

Transcript

AILSA CHANG, HOST:

Over the course of the pandemic, people began noticing something weird happening in the reviews section for Yankee Candles on Amazon. It seemed like whenever there was a spike in COVID cases, there was also an influx of reviews complaining about scentless candles, perhaps because COVID had wiped out some people's sense of smell.

SACHA PFEIFFER, HOST:

Nick Beauchamp of Northeastern University had studied how social media could predict COVID prevalence. So when he got wind of the Yankee Candle phenomenon, he knew just how to proceed.

NICK BEAUCHAMP: I just thought, well, it's easy enough to do. Maybe I'll just try scraping some Amazon reviews and see what the actual trends are.

CHANG: The results of his analysis were clear. When COVID cases surged, there was a corresponding rise in negative candle reviews, even after controlling for seasonality. And he found similar trends for perfume reviews, suggesting it wasn't a Yankee Candle-specific phenomenon.

PFEIFFER: Beauchamp says data points like online reviews can be a useful supplement to more traditional measurements of COVID prevalence, like case counts.

BEAUCHAMP: Those of us who sort of still care about and worry about the pandemic and don't think that it's over are grasping around for other sources of data that can be used to track, you know, new waves and that sort of thing.

PFEIFFER: That's especially true as COVID testing and reporting have changed. Infectious disease doctor Abraar Karan of Stanford University points out that case counts may not present as clear a picture as they used to.

ABRAAR KARAN: A lot of testing got decentralized such that people were testing at home, and so we weren't able to get a good grasp of how many people were actually testing positive. After a certain point, because a number of people tested at home and then they isolated, that data didn't get reported to public health departments.

CHANG: So are Yankee Candle reviews the new COVID metric?

BEAUCHAMP: These kind of things are used in public health, you know, more for research. But at this point in COVID, I don't think candle reviews are going to change kind of our public health strategy.

CHANG: In the meantime, feel free to enjoy those seasonal fall scents, like Spooky Spider Cider. But if you don't smell anything, maybe grab a COVID test before leaving a review. Transcript provided by NPR, Copyright NPR.