By Alistair Smout
LONDON (Reuters) – The majority of people who have had COVID-19 are protected for at least six months to get it back, a study published on Wednesday showed, but older people are more prone to reinfection than younger people.
The study, published in the medical journal Lancet, found that only 0.65% of patients tested positive for COVID-19 a second time after being previously infected during Denmark’s first and second waves. This was much lower than the 3.27% who were positive for the virus using very accurate PCR tests after they were initially negative.
However, the study found that people over the age of 65 have only 47% protection against recurrent infection, compared to 80% protection for younger people.
“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 Steen Ethelberg of Statens Serum Institut, Denmark, said.
“As older people also experience more severe disease symptoms and sadly die, our findings make clear how important it is to implement policies to protect the elderly during the pandemic.”
The authors of the study found no evidence that protection against reinfection decreased over a follow-up period of six months, but said that further studies were needed to assess the protection against reinfection of variants of the coronavirus.
The analyzed data were collected through Denmark’s national testing strategy, in which 69% of the population, or 4 million people, were tested during 2020.
Imperial College London professors Rosemary Boyton and Danny Altmann commented on the results, saying the results showed lower protection and were “more worrying” than previous studies.
“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-efficiency vaccinations is the lasting solution. , “they said. in a linked commentary also published in the Lancet.
(Reported by Alistair Smout; edited by Bill Berkrot)