A recent systematic review of studies found that people who have been vaccinated against COVID-19 and have had a previous SARS-CoV-2 infection, known as having hybrid immunity, have better protection against the Omicron variant than those with only a previous infection. [JAMA Network]
The effectiveness of hybrid immunity against hospital admission or severe disease was 97% at 12 months compared with 75% after infection alone. Effectiveness against reinfection was 42% for hybrid immunity and 25% for previous infection at 12 months.
The findings, published in The Lancet Infectious Diseases, suggest that people with hybrid immunity may not need COVID-19 vaccine booster doses as soon as people who are vaccinated but have never been infected, the authors noted. “Producing estimates of protection for vaccines targeting new variants will be crucial for COVID-19 vaccination policy and decision-making bodies,” the authors wrote.