COVID-19 Might Turn Out To Be Seasonal

Maybe we'll get lucky and avoid big coronavirus outbreaks in the red areas, but I wouldn't count on it. We need to be prepared for ongoing large breakouts as the southern hemisphere enters fall and winter and starts to cool off.

A team of researchers has written a paper about the possible seasonality of COVID-19. Here’s a map of the major outbreaks so far:

As you can see, the biggest centers of infection have occurred within a fairly narrow band of cool temperatures and low absolute humidity:

In the months of January 2020 in Wuhan and February 2020 in the other affected cities, there was a striking similarity in the measures of average temperature (4-9 ºC at the airport weather stations). Average temperatures from a period of 20-30 days prior to the first community spread death in the area showed similar temperatures (3-9 °C at the airport weather stations)….These cities had varying relative humidity (44-84%), but consistently low specific (3-6 g/kg) and absolute humidity (4-7 g/m3).

The authors draw two conclusions. First, we might soon see major outbreaks in a band to the north of the current outbreaks (Manchuria, Central Asia, the Caucuses, Eastern Europe, Central Europe, the British Isles, the Northeastern and Midwestern United States, and British Columbia). Second, this behavior is typical of a seasonal coronavirus, and “it is tempting to expect COVID-19 to diminish considerably in affected areas (above the 30° N’) in the coming months and into the summer.”

This is very tentative stuff, and the authors warn that the coronavirus is new and there is no immunity to it. In previous cases like this, “the initial epidemic acted unpredictably.” So there might be some good news here, but it’s pretty thin. Stay home and keep washing your hands.