Older people who have recovered from Covid cannot assume they are immune to a second attack, according to a new study showing that those under 65 are less susceptible to reinfection.
The study conducted in Denmark found that those under 65 had at least six% protection for at least six months to catch Covid a second time. But those over 65 had only 47% protection.
According to the authors of the research, published in the medical journal Lancet, it is important to take measures to protect the elderly, who are also likely to die from Covid. “Our study confirms what a number of others seem to suggest: re-infection with Covid-19 is rare in younger, healthy people, but the elderly are at greater risk of catching it again,” said Dr Steen Ethelberg of the Statens Serum Institute in Denmark said. .
“As older people also experience more serious illness symptoms and die sadly, our findings show how important it is to implement policies to protect the elderly during the pandemic. Given what is at stake here, the results highlight how important it is for people to adhere to the measures implemented to keep themselves and others safe, even if they have already had Covid-19. Our insights can also inform policies focused on broader vaccination strategies and the easing of closure restrictions.
Denmark has a very comprehensive testing program, with PCR water tests made available to anyone who wants one, whether they have symptoms or not. More than two-thirds of the population, 4 million people, were tested in 2020. The researchers looked at the ratios of people who tested positive in the first wave, between March and May, and again in the second wave, from September to December. . They also looked at second infections during a pandemic during a group of 2.5 million people at any one time.
Prof Rosemary Boyton and Prof Daniel Altmann, of the Imperial College London, say in a commentary in the magazine that the findings are sobering because the reports have previously suggested that reinfection is extremely rare. In light of this, “many people will find the information reported … about protection by natural infection relatively worrying,” they write. “Only 80% protection against reinfection in general, and it drops to 47% in people aged 65 and older, is more worrying than in previous studies.”
They say the study strengthens the case for mass immunization programs – to include those who have contracted Covid in the past.
“This data is, if necessary, a confirmation that the hope for protective immunity through natural infections for Sars-CoV-2 may not be within our reach, and that a global vaccination program with high efficacy is the lasting solution. is, “they write. .