The odds of getting infected with the virus, which causes COVID-19, were 2.3 times higher among people who had been infected before when compared to those who were fully vaccinated, according to the new report.
Researchers in Kentucky teamed with Centers for Disease Control and Prevention (CDC) officials to carry out the case-control evaluation of the link between vaccination and infection.
They used Kentucky’s National Electronic Disease Surveillance System to find COVID-19 cases and checked for people who got infected a second time between May 1 and June 30 of this year.
They also utilized the state’s immunization registry to look for fully vaccinated persons.
Researchers ended up with two groups. The first group of 246 was called case-patients, who experienced a second COVID-19 infection. The second was a control group of 492 who did not.
Some of the case-patients were fully vaccinated but still got a second infection, according to researchers. Still, the percentage of those who went unvaccinated and got infected again was higher, they found.
“These data further indicate that COVID-19 vaccines offer better protection than natural immunity alone and that vaccines, even after prior infection, help prevent reinfections,” 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,” added Dr. Rochelle Walensky, the agency’s director.
Some existing research tilts the opposite direction of the study’s conclusions. Multiple studies have indicated that vaccination does not provide more protection than prior infection.
Dr. Jeffrey Klausner, clinical professor of preventive medicine at the University of Southern California’s Keck School of Medicine, conducted one of those studies.