People who have recovered from COVID-19 are at little risk of contracting the disease again, according to a study published last week.
Researchers in Qatar examined a cohort of over 353,000 people using national databases that contain information about patients with polymerase-chain-reaction-confirmed infections.
The studied population contracted COVID-19, the disease caused by the CCP (Chinese Communist Party) virus, between Feb. 28, 2020, and April 28, 2021.
Reinfections were counted if a person tested positive at least 90 days after their first infection.
After excluding approximately 87,500 people with a vaccination record, researchers found that those with immunity due to having recovered from COVID-19 had little risk of reinfection or severe cases of the disease.
Just 1,304 reinfections were identified. That means 0.4 percent of people with natural immunity and without a vaccination record got COVID-19 a second time.
The odds of severe disease were 0.1 times that of primary infection, according to the study. Just four such cases were detected.
No cases of death were recorded among those who got infected a second time.
The study was published in the New England Journal of Medicine. It was funded by Weill Cornell Medicine–Qatar, Qatar’s Ministry of Public Health, the Hamad Medical Corp., and Sidra Medicine.
The researchers, Laith Abu-Raddad with Weill Cornell Medicine–Qatar and Dr. Robert Bertolini with Qatar’s Ministry of Public Health, had previously assessed the effectiveness of natural immunity against reinfection as being 85 percent or greater.
“Accordingly, for a person who has already had a primary infection, the risk of having a severe reinfection is only approximately 1% of the risk of a previously uninfected person having a severe primary infection,” they said.