Can you get sick of Covid-19 again? And how long does immunity last? A maxi study conducted in Denmark, which assessed the country’s 2020 reinfection rates, sought to answer precisely these questions. The results, published on The Lancet, confirmed that the cases of reinfection are rare and they are also more common among the elderly.
In fact, the study showed that the over 65 are more at risk of getting infected again. In this age group the protection from repeated infections is equal to 47%, compared to 80% recorded among the younger population.
It must be said, however, that one previous infection acts as a shield on most people healed. In fact, according to the data collected by the study, only 0.65% of patients had a positive test twice, compared to 3.27% of people who tested positive for the first time (5 times higher infection rate).
Covid-19, stable immunity for more than six months
Another interesting fact that emerged from the research is that immunity remains stable for more than 6 months. “There is no evidence to indicate that protection falls within 6 months of infection”, he highlighted Daniela Michlmayr, of the States Serum Institut, who also recalled that “It has been shown that the closely related Sars and Mers coronaviruses confer an immune protection against reinfection lasting up to 3 years”.
Anyone who has had Covid-19 must still get vaccinated
The greater risk of getting sick in the elderly also highlights theimportance of measures to protect them e “Priority on vaccines, even for those who are cured”. The study in fact suggests that, broadly speaking, people have had the virus they should still be vaccinated, as it cannot be relied upon exclusively “On natural protection”.
The study did not evaluate the variants
The Danish researchers relied on the data collected as part of the national free swab screening initiative which allowed to test more than two thirds of the population in 2020. Given the time frame referred to, it was therefore not possible to estimate the protection against reinfection from variants of Sars-CoV-2. Precisely for this reason, the authors stressed the importance and need for further studies.
A separate focus was also dedicated to health workers, which have greater exposure to the virus. Also in this case the results obtained were similar: 1.2% of those who had already had Covid in the first wave were reinfected, while the infection rate of those who had never met the virus was equal to 6. ,2%.