A Way to Avoid the Coronavirus?

Virus epicentres mapped to mean daily temperatures.

An enduring mystery of the coronavirus is why it has not yet run rampant in the Philippines.

Filipinos are gypsies. They are working in large numbers in all the other countries of the region, some of which have been hard hit—not to mention being most of the crew on most cruise ships. Because home is near, in East Asia they are always flying in and out—it is not unusual to fly in to Manila for the weekend. The Philippines also had, as I recall, the first confirmed case outside of China. Yet the numbers are still small, and there has been no confirmed community spread.

Another why has the virus been so much more disruptive and deadly in Italy than it has been in South Korea? South Korea got it sooner, and things looked desperate. But the number of new cases has levelled off, and there have been far fewer fatalities.

Wait, there’s more. Why did Vietnam and Singapore, close to China and with so many connections, have a rash of early cases, but the victims seem to recover, and not to spread; while Iran, much further away from the Chinese epicentres, and with much less commerce in that direction, explode with serious cases?

I speculated this was because of better social cohesion in the face of disaster.

But now someone has come up with another explanation, that seems to me to make sense. The places where the virus has been particularly successful at spreading, they discover, lie along a narrow band of latitude. Or more specifically, of temperature and relative humidity. These scientists suggest that the virus needs a steady temperature of 5-11 degrees Celsius and 47-79% relative humidity to spread. All the most affected areas share these parameters.

This makes sense in terms of what we know about viruses. They commonly die back in summer. They commonly thrive only within particular climactic parameters.

So why has the virus stopped spreading so swiftly in South Korea? It may not be that South Korea’s containment measures are so successful. It may simply be that the temperature is getting higher as spring takes hold, putting them on the fringe of the virus-fertile zone.

If this is right, and it looks right, this is good news. It suggests the virus may go dormant throughout the northern hemisphere over the next few months. Buying us all some valuable time.

The bad news is that southern Canada is about to move into the kill zone.

But even so, spring in northern climes may not be that favourable to the virus, as the temperature is not steady day to day, and changes quickly.

And if we can aggressively delay its spread, we might hold it back until the warmer weather comes.

In the meantime, this suggests a useful strategy for retirees, those most vulnerable, or those who actually have the virus and are in self-quarantine, to avoid infection. Check the temperature and humidity daily. If they are within the danger zone, postpone any errands. If they are out of the danger zone, it may be quite safe to venture outside.