Unvaccinated people are twice as likely to be re-infected with the Covid-19 virus as fully vaccinated people, according to a study released Friday August 6 by US health authorities.
According to the Centers for Disease Prevention and Control (CDC), the main federal public health agency in the United States, the findings of the study confirm that "
any eligible person can be vaccinated against Covid-19 , regardless of their previous status of infection with SARS-CoV-2
”, the virus that causes Covid-19.
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Some American politicians, including Republican Senator Rand Paul, have said they do not intend to be vaccinated because of their natural immunity obtained after contracting the new coronavirus. The CDC study is based on 246 adults in Kentucky who were reinfected with the virus between May and June this year after being infected for the first time in 2020. They were compared to 492 people "
case-controls
", according to their sex, age and when they tested positive.
According to the results of the study, unvaccinated people were 2.34 times more likely to be re-infected compared to people fully vaccinated with sera from Pfizer, Moderna or Johnson & Johnson. Researchers are still struggling to understand the exact duration of acquired immunity after infection and this could be altered by the emergence of new variants, according to the study.
Laboratory studies have shown that blood samples taken 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 limitations of this study is, however, that it was carried out before the appearance of the Delta variant, which is now the dominant strain of the virus in the United States.