Influenza, which usually rages throughout the Northern Hemisphere at this time of year, has become virtually invisible.
This is a small bright spot in the midst of Covid-19, although the number of people rescued from a flu death pales in comparison to the number dying from the new pandemic. It also raises questions that doctors around the world are likely to grapple with for years: if flu can be virtually eradicated this season, why not every season? What steps help the most to prevent the flu from spreading?
“It simply came to our notice then. We are in a historic, incredible situation, ”said Norio Sugaya, a pediatrician who serves on a World Health Organization flu committee.
The WHO says the measures that people and governments are taking to prevent the spread of Covid-19, such as wearing masks and restricting public gatherings, have probably helped keep the flu in check. Increased flu vaccination rates may also contribute.
Another hypothesis claims that the widespread spread of SARS-CoV-2, the virus that causes Covid-19, in countries such as the US could play a role in blocking influenza by lifting people’s immunity to other viruses. One study in the spring of 2020 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 flu viruses. The investigation into the hypothesis is just beginning.