Here’s a worrying statistic: We’re just a few months into 2021, and in the U.K., public-health authorities have yet to detect any cases of flu. The reason, experts believe, is that the mask wearing, social distancing and lockdowns designed to slow the spread of coronavirus have essentially wiped out the flu virus. Flu numbers are down all over the world.
This is good news, of course. So why is it also worrying? If these measures have also kept the flu at bay, they may have kept other infectious agents under control as well, including some that are far more dangerous. And when we emerge from the Covid crisis and start to relax public-health measures — in particular, allowing international air travel to resume — these more dangerous agents could surprise us with a violent resurgence.