SARS-CoV-2 Reinfection More Likely in Unvaccinated Individuals

Among Kentucky residents who were infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in 2020, those who were unvaccinated against COVID-19 had an increased likelihood of reinfection in May to June 2021 compared with those who were vaccinated, according to research published in the Aug. 6 early-release issue of the U.S. Centers for Disease Control and Prevention Morbidity and Mortality Weekly Report.

Alyson M. Cavanaugh, Ph.D., from the CDC in Atlanta, and colleagues present the findings of a case-control evaluation of the correlation between vaccination and SARS-CoV-2 reinfection in Kentucky during May to June 2021 among individuals with previous SARS-CoV-2 infection in 2020.

The researchers found that the odds of reinfection were increased among Kentucky residents who were not vaccinated versus those who were fully vaccinated (odds ratio, 2.34; 95 percent confidence interval, 1.58 to 3.47). There was no association observed for partial vaccination with reinfection (odds ratio, 1.56; 95 percent confidence interval, 0.81 to 3.01).

"If you have had COVID-19 before, please still get vaccinated," Rochelle Walensky, M.D., M.P.H., director of the CDC, said in a statement. "This study shows you are twice as likely to get infected again if you are unvaccinated. Getting the vaccine is the best way to protect yourself and others around you, especially as the more contagious delta variant spreads around the country."