How will COVID-19 affect the coming flu season? Scientists struggle for clues
Science’s COVID-19 reporting is supported by the Pulitzer Center and the Heising-Simons Foundation.
In March, as the Southern Hemisphere braced for winter flu season while fighting COVID-19, epidemiologist Cheryl Cohen and colleagues at South Africa’s National Institute for Communicable Diseases (NICD) set up a plan to learn from the double whammy. They hoped to study interactions between seasonal respiratory viruses and SARS-CoV-2, which causes COVID-19. Does infection with one change a person’s risk of catching the other? How do people fare when they have both?
But the flu season—and the answers—never came. NICD’s Centre for Respiratory Disease and Meningitis, which Cohen leads, has logged only a single flu case since the end of March. In previous years, the country’s surveillance platforms have documented, on average, about 700 cases during that period, Cohen says. “We’ve been doing flu surveillance since 1984, and it’s unprecedented.”
Some cases probably got overlooked as clinics temporary closed and people with mild symptoms avoided medical offices and clinics, Cohen says. “But I don’t believe it possible that we’ve entirely missed the flu season with all of our [surveillance] programs.” Apparently, travel restrictions, school closures, social distancing, and mask wearing have all but stopped flu from spreading in South Africa. Similar stories have emerged from Australia, New Zealand, and parts of South America.