In 2020, we learned that negative candle reviews are a (very) informal proxy for Covid cases.
The results were surprisingly clear: Before 2020, reviews of the top scented candles hovered between 4 and 4½ stars, year after year. Since January, however, those grades have fallen roughly one full star.
Unscented candle reviews, meanwhile, don't show the same pattern.via Washington Post, December 2020
As Omicron surges, scented candle ratings are taking a hit once again. Protocol emphasizes that the findings are observational, not scientific, and Northeastern University professor Nick Beauchamp notes that "no smell" complaints commonly rise in the winter. Still, if you cannot detect the wafting scents of your holiday scented candle, it's not a bad idea to take a Covid test.