2020 polio data scarce due to COVID-19 pandemic, CDC says

Photo of Jordan Fenster

As the COVID pandemic spread, the reported number of polio cases dropped globally, but not necessarily because there’s fewer polio cases out there.

The most common way of detecting polio in children is through surveillance for acute flaccid paralysis. Reported cases dropped 33 percent globally from January to September of 2020, compared to the same period in 2019, according to the Centers for Disease Control and Prevention.

“The decline in polio surveillance coincided with the spread of COVID-19,” the CDC wrote.

Polio effectively has been eradicated in the United States, since the widespread application of a vaccine in the first half of the 20th century. There have been no reported cases of polio originating in the United States since 1979.

Polio surveillance is organized by regions. The American region, which includes all of North America and South America, saw a 45 percent decrease of reported polio surveillance data in 2020 compared to 2019.

The African region saw the smallest decrease, with 13 percent less polio surveillance in 2020.

The reasons for declines in polio surveillance data vary, according to the CDC.

“In several countries, polio surveillance officers have played an important role in supporting the COVID-19 response, which affected the time they spent on polio surveillance activities,” but the pandemic wasn’t always the culprit.

For example, a work strike by polio field staff members in the Central African Republic resulted in less data collection.

Nonetheless, a decline in data sharing and collection and “delays in transport and limited surveillance activities suggest that global polio surveillance was negatively affected in 2020 by the COVID-19 pandemic,” the CDC wrote.