Doctors in France are calling it the immunity debt: When people avoided each other during the pandemic, they failed to build up the immunity against viruses that comes from normal contact.
As regular life resumes, society may find payments on that debt coming due, in the form of worse-than-normal viral disease outbreaks.
In early June, 16-month-old Toranosuke Tsukidate came down with a common virus that caused a fever topping 106 degrees Fahrenheit. The bug was spreading rapidly through his Tokyo daycare, said his mother, Miwako Tsukidate, 27, and the boy was hospitalized for oxygen treatment for a week.
By the time Toranosuke was discharged, his mother observed the beds around him filling up with children suffering the same ailment, which is usually more common in the fall. “I was surprised to see how it took off so quickly, and I was also surprised to see it spreading at this time of the year,” Ms. Tsukidate said.
At Perth Children’s Hospital in Australia, infectious diseases researcher David Foley isn’t surprised. His country experienced a similar out-of-season flare-up of the virus that infected Toranosuke—respiratory syncytial virus or RS virus—during the Southern Hemisphere’s summer months following an unusually quiet winter.