The risk of COVID-19 reinfection is more than five times higher with the omicron variant than with the delta variant, a new study by the Imperial College London suggests.
Researchers also said that there was no sign that the infections were any milder, though data on hospitalizations is still “very limited.”
The results of the study, which has yet to be peer-reviewed, were based on data from the U.K. Health Security Agency and National Health Service on people who tested positive for COVID-19 in England, excluding those who had traveled abroad, from Nov. 11 to Dec. 12.
“Omicron was associated with a 5.4-fold higher risk of reinfection compared with Delta,” researchers wrote, adding that they found “no evidence (for both risk of hospitalization attendance and symptom status) of Omicron having different severity from Delta, though data on hospitalizations are still very limited.”
“We find strong evidence of immune evasion, both from natural infection … and from vaccine-induced protection,” researchers wrote.
Natural immunity only offered 19% of protection against omicron. People who were fully vaccinated — or have had two doses of either the AstraZeneca or the Pfizer vaccines — had no more than 20% protection against omicron.
The good news is that a booster shot dramatically increased immune defense: up to 80% more protection against the new variant.
The U.K. has been battling a devastating new wave of coronavirus infections driven by the fast-spreading omicron variant, which is expected to quickly become the dominant strain of the virus.
A record number of new infections have been confirmed in Britain for the last three consecutive days, with 93,045 cases recorded on Thursday, including 111 deaths.
The previous record-high, set on Jan. 8, was 68,053 cases.
