The American company Moderna announced on Wednesday January 26 that it had started clinical trials for a booster dose of a vaccine designed specifically against the Omicron variant of SARS-CoV-2.
These trials will include 600 adults, half of whom already received two doses of Moderna’s Covid-19 vaccine at least six months ago and the other half received not only those initial two doses as well as at least three months, the booster dose already authorized. The specific booster against Omicron will therefore be assessed both as a third or fourth dose.
The company also reported results on the effectiveness against Omicron of the recall already authorized. According to the company, six months after the booster injection, levels of neutralizing antibodies against Omicron were reduced six-fold from the peak seen twenty-nine days after the sting, but remained detectable in all participants. These data were obtained by analyzing the blood of twenty people who received the booster dosed at 50 micrograms (half as much as the first two injections).
“We are reassured of the persistence of antibodies against Omicron six months after the currently authorized recall, said in a press release Stéphane Bancel, the general manager of Moderna. However, given the long-term threat posed by immune escape from Omicron, we are moving forward with our specific vaccine candidate recall against Omicron. »
A drop in cases in several countries
The Pfizer-BioNTech alliance also announced this week that it has begun trials to test its own specific vaccine against Omicron. Pfizer is evaluating its formula not only as a booster, but also for the initial round of injections, in previously unvaccinated people.
These two vaccines are based on messenger RNA technology, which makes it possible in particular to be able to update them relatively easily to follow the evolution of the mutations specific to the new variants.
Several countries, including the United States, have seen a drop in cases due to the wave caused by Omicron, the most transmissible variant detected at this stage, but the number of contaminations in the world continues to increase.