Cellular immunity elicited by the BioNTech/Pfizer and Johnson & Johnson Covid-19 vaccines is effective against the Omicron coronavirus variant, according to a study, suggesting vaccines will protect against severe disease even if the antibody responses against the strain are not as strong or durable.

The findings, contained in a new Harvard medical school study, add to evidence that the current vaccines hold up against severe Covid outcomes, and could help health authorities to decide whether to switch to Omicron-targeted jabs.

“These data suggest that current vaccines may provide considerable protection against severe disease with the Sars-Cov-2 Omicron variant despite the substantial reduction of neutralising antibody responses,” the researchers wrote in the study made public on Monday. The paper has not been peer-reviewed yet.