A study pointed out that the decline in immunity caused by vaccination against covid-19 occurs more slowly among people who have been infected by the coronavirus. Prepared by researchers from British institutions, the research was published in one of the most prestigious scientific journals in medicine, the New England Journal of Medicine.
Among participants not infected with the coronavirus, the effectiveness of the vaccine dropped from 85% to 51% about seven months after the second dose. The immunity of people immunized with the vaccine and who were contaminated, remained high at about 68% over a year after infection.
But the authors consider that the study was unable to assess the period in which immunity would remain high in the case of reinfected individuals. “We have shown that immunity remains high for up to a year, and then it starts to drop. Due to the limitation of follow-up, the duration of the immunological protection of the reinfected remains unclear”, says the article.
Among people infected for the first time, 61% reported symptoms of covid-19 and 13% reported other symptoms. Among those reinfected, 34% said they had symptoms of covid-19 and 20% mentioned other symptoms.
The study analyzed the duration and effectiveness of immunity in healthcare workers in the UK, considering an interval of more than ten months after the first dose of the covid-19 vaccine. 35,768 volunteers participated.