The flu, which usually hits the northern hemisphere at this time of year, has become virtually invisible.
It is a small bright spot in the midst of Covid-19, although the number of people saved from a flu death is less than the number of people who died from the new pandemic. It also poses questions that doctors around the world are likely to be struggling with for years: if the flu can be almost wiped out this season, why not every season? Which steps most help to prevent the spread of flu?
“This is an extremely intriguing phenomenon. We are in a historic and unbelievable situation, ”said Norio Sugaya, a pediatrician who works on an influenza committee at the World Health Organization.
The WHO says that measures that people and governments are taking to prevent the spread of Covid-19, such as wearing masks and limiting public meetings, have probably helped to control the flu. Rising flu vaccination rates may also be contributing, he says.
Another hypothesis holds that the widespread spread of SARS-CoV-2, the virus that causes Covid-19, in countries like the United States, may play a role in blocking the flu, increasing people’s immunity against other viruses. A spring 2020 study in New York City found that people who tested positive for SARS-CoV-2 were much less likely to carry other common viruses, such as the flu virus. Still, research on this hypothesis is just beginning.