More Evidence Hybrid Immunity Confers Highest Level of COVID Protection--studies

Hybrid immunity from a COVID-19 infection plus a vaccine provided an immune boost against symptomatic disease, as well as severe outcomes, Brazilian researchers found.

Among people who survived a COVID infection from Feb. 24, 2020 to Nov. 11, 2021, vaccine effectiveness against symptomatic disease at least 14 days after series completion was 44.0% (95% CI 31.5-54.2) for Johnson & Johnson's vaccine and 64.8% (95% CI 54.9-72.4) after two doses of Pfizer's vaccine, reported Julio Croda, MD, PhD, of Universidade Federal de Mato Grosso do Sul in Brazil, and colleagues.

Moreover, vaccine effectiveness against COVID-related hospitalization or death was 57.7% (95% CI -2.6 to 82.5) for Johnson & Johnson's vaccine, and 89.7% (95% CI 54.3-97.7) for Pfizer's, the authors wrote in Lancet Infectious Diseases. ...orized for use in the U.S.

"There has been ongoing public debate about whether previously infected individuals need to be vaccinated," said Croda in a statement. "Our results suggest that vaccine benefits far outweigh any potential risk and support the case for vaccination, including the full vaccine series, among individuals with prior SARS-CoV-2 infection." ...

A second study in Lancet Infectious Diseases found the lowest number of reinfections and hospitalizations among those with hybrid immunity. ...