COVID-19 measures have all but wiped out influenza in the Southern Hemisphere

Countries across the Southern Hemisphere are reporting significantly lower cases of influenza, respiratory syncytial virus, and other seasonal respiratory viral infections this year. Health experts attribute the trend to such measures as mask use and restrictions on air travel amid the COVID-19 pandemic. Claudia Cortés, an infectious-disease specialist in Chile, says of approximately 1,300 COVID-19 patients she treated since late March, only a handful had influenza. Chile recorded 1,134 seasonal respiratory infections so far this year, compared with 20,949 during the same period last year. In the first 2 weeks of July—the equivalent to early January in the Northern Hemisphere—Chile reported no new confirmed influenza cases. Similarly, Australia registered only 85 new laboratory-confirmed influenza cases in the last 2 weeks of June, compared with 22,047 confirmed cases for the 2 weeks through June 30 a year earlier, according to Australia’s National Notifiable Diseases Surveillance System. Sylvain Aldighieri, MD, deputy director of the Department of Health Emergencies at the Pan American Health Organization, cautions that hospitals and physicians in the United States and Europe should prepare for a typical influenza season as their economies reopen and restrictions are lifted.