People who got Covid in the early stages of the pandemic weren’t especially safe from catching the virus again when the omicron variant swept the world, according to a study.
Those who were infected with alpha, beta and delta variants were only 36% better protected from reinfection with omicron about 10 months later than people who hadn’t had the disease, University of Washington researchers said Thursday in the Lancet. However, the group was able to avoid hospitalization with omicron, and death, almost 90% of the time over the same period.
The findings, derived from a meta-analysis of 65 studies from 19 countries, may help health officials steer vaccination campaigns and form policy recommendations. The Covid-19 pandemic was particularly hard to cope with because the behavior of the novel virus was mostly shrouded in mystery, and researchers are still uncovering new information about how it affects people.
The study suggests those infected with pre-omicron variants are well protected against older variants but should still take steps to prevent reinfection, according to Stephen Lim, a professor and senior director at the Institute for Health Metrics and Evaluation at the University of Washington, and lead author of the report.
“It’s much more important for those individuals who were previously infected with a pre-omicron variant to be up to date on their vaccine schedules,” Lim said.
Vaccinations are also the safest way to gain protection from the virus, particularly with people who are older or who have other health conditions, he said. More than 6.8 million people have died from Covid since the pandemic started, according to the World Health Organization.
Researchers still have more work to do, particularly to understand omicron and later variants, said Hasan Nassereldine, a postdoctoral scholar at the Institute for Health Metrics and a co-author of the report, in a statement.
“Further research is also needed to assess the natural immunity of emerging variants and to examine the protection provided by combinations of vaccination and natural infection.”
