The vaccine makers Pfizer and BioNTech say a booster dose of updated versions of their Covid-19 vaccine, modified specifically to combat the Omicron variant, has been shown to generate a higher immune response against that variant.
United States medicine officials will meet next week to discuss whether to update the Covid-19 vaccines in use in time for the northern autumn, so that they target Omicron.
Pfizer and BioNTech say versions of a shot targeting just the BA.1 Omicron subvariant have shown more than a ten-fold increase in antibodies working against it.
Their early studies suggest these Omicron vaccine candidates also neutralise the more recent BA.4 and BA.5 subvariants, though to a lesser extent.
The companies say they are continuing to collect data on how well the boosters perform versus the more recently circulating strains.
Moderna has also made a redesigned vaccine targeting the BA.1 Omicron subvariant. The company said its updated vaccine worked well against more recent Omicron subvariants, and that it was moving forward with plans to ask regulators for approval.