WASHINGTON (AFP) – United States (US) biotech company Moderna announced on Wednesday that it has begun clinical trials of a booster dose of vaccine designed specifically to combat the Omicron variant of the coronavirus.
The trials will involve a total of 600 adults – half of whom have already received two doses of Moderna’s COVID-19 vaccine at least six months ago, and half of whom have received two doses plus the previously authorised booster dose.
The booster specifically targetting Omicron will therefore be evaluated as both a third and a fourth dose.
The company also reported results on the efficacy against Omicron of the booster that has already been authorised.
It said that six months after the booster injection, the levels of neutralising antibodies against Omicron were reduced by six times from the peak observed 29 days after the injection – but remained detectable in all participants.