Now winter is over in the Southern Hemisphere and beginning in the North. And though it’s still early in the season, already things look radically different to how they ordinarily would.

As of September, the World Health Organization (WHO) reported the missing flu cases were a global phenomenon, with significantly lower levels than would be expected, from tropical Africa to the Caribbean. For the week beginning 7 September, the flu tracker FluMart recorded just 12 lab-confirmed cases of the flu on the entire planet.

“What we’re seeing in Australia, New Zealand, South America, Hong Kong, are really, really attenuated seasons of not just the flu, but also respiratory syncytial virus (RSV),” says Sarah Cobey, an epidemiologist at the University of Chicago.

Of course, there are many possible reasons that cases might be down this year. People could be afraid to seek medical treatment, and in some places, there it’s possible that fewer tests were conducted as resources were diverted elsewhere. But many experts suspect that the trend is down to physical distancing and improvements to hygiene in the wake of the pandemic.