COVID-19 Reinfections Occur, but Remain Rare

By Reuters Staff

September 24, 2020

(Reuters) - Another case of reinfection after recovery from COVID-19 has been reported, this time in a healthy young military healthcare provider at a U.S. Department of Defense hospital in Virginia.

The individual was first infected by a patient in March. He recovered within 10 days and "returned ... to excellent health," his doctors report in Clinical Infectious Diseases. Fifty-one days later, he was reinfected by a household member. Genetic studies showed the first and second infections to be from slightly different strains of the virus.

The reinfection made him sicker, perhaps because the second strain was more potent, or the household contact infected him with a higher load of virus, doctors said. It was also possible antibodies from the first infection may have triggered his immune system to respond more strongly to the virus the second time his body encountered it.

COVID-19 reinfections are still rare. Kristian Anderson, professor of immunology and microbiology at Scripps Research in La Jolla, California, recently told Reuters virus reinfections are always possible.

"We don't know at what frequency reinfections (with the new coronavirus) occur and how that might change over time," Anderson said. Without further studies, "we can't conclude what a single case of reinfection means for longevity and robustness of COVID-19 immunity and relevance for a future vaccine," she added.

SOURCE: Clinical Infectious Diseases, online September 19, 2020.