Unvaccinated people are twice as likely to be reinfected with the coronavirus as people who have been fully vaccinated, according to a new study by the Centres for Disease Control and Prevention (CDC) in the United States.
The study, which was published on Friday, also stresses that any eligible person can be vaccinated against Covid-19, whatever their status before being infected with the virus.
“If you have had Covid-19 before, please still get vaccinated,” CDC Director Rochelle Walensky 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.”
Some U.S. politicians, such as Republican Senator Rand Paul, have said they do not intend to get the vaccine because they acquired natural immunity after surviving the virus.
The CDC study is based on 246 adults in the state of Kentucky who were reinfected between May and June this year after contracting the virus in 2020. They were compared to another set of 492 cases, based on sex, age and the date on which they tested positive.
The results showed that the chances of being reinfected were 2.34 times higher among the unvaccinated than among people fully vaccinated with the Pfizer, Moderna or Johnson & Johnson vaccine.
However, the researchers have not yet been able to determine exactly how long immunity acquired after an infection lasts. Additionally, that immunity can be altered by the emergence of new variants, the study showed.
Laboratory studies indicate that blood samples from people infected with the original strain of the Wuhan virus had a weak immune response to the Beta variant, first identified in South Africa.
One of the limits of the new study is, nevertheless, that it was conducted before the appearance of the Delta variant, now the dominant strain in the United States.
The Brussels Times