It was discovered that the immunity produced by an infection was “at least as high, if not higher” than that given by two doses of an mRNA vaccine.
Immunity acquired through a Covid infection offers potent, long-lasting protection against an illness’s most severe outcomes, according to new research.
The study, published in The Lancet, discovered that acquired immunity from an infection reduced the risk of hospitalisation and death from a Covid reinfection by 88% for at least 10 months.
The protection is comparable to that offered by two doses of an mRNA vaccine.
“This is really good news, in the sense that protection against severe disease and death after infection is really quite sustained at 10 months,” said the senior study author, Dr. Christopher Murray, the director of the Institute for Health Metrics and Evaluation at the University of Washington, reported NBC.
The discoveries could provide consolation for the deadly omicron outbreak of last winter. With so many people infected, Murray said, many still profit from that defence against serious illness.
However, given the risks of Covid, especially in the case of those who are not vaccinated, experts emphasise that vaccination is the preferred method of obtaining immunity.
“The problem of saying ‘I’m gonna get infected to get immunity’ is you might be one of those people that end up in the hospital or die,” Murray said. “Why would you take the risk when you can get immunity through vaccination quite safely?”
The research represented the biggest meta-analysis to date to examine immunity after infection. It compared the risk of developing Covid once more in individuals who had recovered from infections to individuals who had not been infected through September and included 65 studies from 19 different countries.
Those who had acquired hybrid immunity, which is immunity resulting from both an infection and a vaccination, were not included. The now-dominant XBB.1.5 and other Omicron sub-variants that first appeared in the late autumn and early winter of last year were also excluded.
People could re-infect, especially with an omicron subvariant, despite the fact that protection against severe illness remained high.
This is consistent with the fact that protection against symptoms deteriorates more quickly than protection against hospitalisation and death.