A woman gets 4th jab at a vaccination centre in Doncaster, U.K., on 28 April 2022. NurPhoto/Getty Images Current vaccines protect most people against severe COVID-19 from all SARS-CoV-2 variants. Breakthrough infection from new variants is increasingly common in people who have been previously vaccinated or had the infection. Two new preprint studies suggest that breakthrough Omicron infection may give vaccinated people greater resistance against new Omicron variants.
A peer-reviewed study has also found that the immunity from vaccination can be enhanced by an Omicron infection, but that Omicron infection alone gives little immunity to other variants. The researchers suggest that Omicron-based booster vaccines may increase resistance to new COVID-19 variants. With little sign that the COVID-19 global pandemic will end any time soon, the hunt is on for effective ways to prevent repeated infections. The rapidly developed vaccines are very successful in preventing severe illness, hospitalization, and death, but new variants still cause breakthrough infections in many people. Now, two preprint studies, which have not yet been peer-reviewed, have found evidence that a breakthrough Omicron infection can afford additional protection to those who are already vaccinated. A third, peer-reviewed study, has confirmed this finding.
The first study, sponsored by BioNTech — which makes the Pfizer vaccine — found an increase in memory B cellsTrusted Source and cross-variant neutralization after breakthrough infection.
The second, an international study led by scientists at the University of Washington, identified an ultrapotent antibody that appears to work against multiple Omicron variants, and detected neutralizing activity by antibodies in the lining of the nose following breakthrough infection. Breakthrough infection boosts defence The BioNTech study used a cohort of people who had been double or triple vaccinated. They were divided into four groups: Double vaccinated who had not experienced breakthrough infection after vaccination. Triple vaccinated with no breakthrough infection. Double vaccinated with breakthrough infection by SARS-CoV-2 Omicron. Triple vaccinated with breakthrough infection by SARS-CoV-2 Omicron. The researchers tested blood samples taken from all participants and assessed the serum neutralizing capacity — the ability of antibodies to stop the virus from binding to receptors and replicating. They performed neutralization tests using both a pseudovirus (a version of the virus that cannot cause disease) and a live virus.
