In a study of COVID-19 infections in Kentucky among people who were previously infected with SAR-CoV-2, researchers found that unvaccinated people were more than twice as likely to be reinfected with COVID-19 than those who were fully vaccinated after initially contracting the virus, the Centers for Disease Control and Prevention (CDC) said in its Morbidity and Mortality Weekly Report.
The agency said the data indicate that COVID-19 vaccines offer better protection than natural immunity alone and that vaccines, even after prior infection, help prevent reinfections.
The report details the findings of a case-control evaluation of the association between vaccination and SARS-CoV-2 reinfection in Kentucky during May–June 2021 among people previously infected with SARS-CoV-2 in 2020.
Overall, 246 cases met eligibility requirements and were successfully matched by age, sex, and date of initial infection with 492 controls. Among the population included in the analysis, 60.6% were female, and 204 (82.9%) case-patients were initially infected during October–December 2020.
Among cases, 20.3% were fully vaccinated, compared with 34.3% of controls.