Less Than 1 Percent of COVID-19 Patients Experience Reinfection

Reinfection following COVID-19 is possible, but rare, according to a study recently published in Clinical Infectious Diseases.

Adnan I. Qureshi, M.D., from the University of Missouri in Columbia, and colleagues assessed the rate of reinfection, associated factors, and mortality during follow up in 9,119 patients with severe acute respiratory syndrome coronavirus 2 infection. Patients received serial tests in one of 62 health care facilities between Dec. 1, 2019, and Nov. 13, 2020. Reinfection was defined as two positive tests during an interval >90 days following resolution of first infection determined by two or more consecutive negative tests.

The researchers found that reinfection occurred in 0.7 percent of patients. The mean period between two positive tests was 116 days. Asthma (odds ratio [OR], 1.9) and nicotine dependence/tobacco use (OR, 2.7) were associated with reinfection. Compared to the primary infection, there was a significantly lower rate of pneumonia, heart failure, and acute kidney injury during reinfection, although two deaths were associated with reinfection.

"This is one of the largest studies of its kind in the United States, and the important message here is that COVID-19 reinfection after an initial case is possible, and the duration of immunity that an initial infection provides is not completely clear," Qureshi said in a statement.