Sanofi SNY, +5.95% SAN, +5.02% and GlaxoSmithKline GSK, +2.20% said Friday that their experimental bivalent COVID-19 booster had a 72% efficacy rate against omicron, and they now plan to submit the data to regulators. The recombinant protein booster protects against the original strain of the virus as well as the beta variant, a strain of the virus that is no longer in circulation but that shares mutations with omicron that allow both variants to "escape" antibodies. When this happens, people who are vaccinated or have been previously infected can get sick again. "Today's results reinforce the strong potential for the beta antigen to confer broad protection against multiple strains that cause COVID-19," Thomas Triomphe, Sanofi's EVP of vaccines, said in a news release. The Phase 3 clinical trial enrolled more than 13,000 adults; the booster had a 65% efficacy rate against symptomatic COVID-19 infections, 72% efficacy rate against omicron-confirmed cases, and 75% efficacy rate against symptomatic infection in people who have already tested positive for the virus. U.S.-listed shares of Sanofi are up 0.6% so far this year, while the S&P 500.