New COVID-19 Vaccine Shows 100% Efficacy Against Severe Cases, Hospitalization: Makers

A new vaccine developed by French drugmaker Sanofi and its British partner GlaxoSmithKline offers its recipients 100% protection against severe cases of COVID-19, the makers said Wednesday.

In its Phase 3 clinical trial, the Sanofi-GSK vaccine was found to be 100% effective in preventing severe COVID-19 infections and hospitalizations and 75% effective in preventing moderate-to-severe illness. The makers also found that their shot was 57.9% effective against any symptomatic cases, noting that the efficacy was "in line with expected vaccine effectiveness in today’s environment dominated by variants of concern."

In a trial where the shot was used as a booster dose, the Sanofi-GSK vaccine increased antibody levels in recipients by 18- to 30-fold, the makers said in a press release.

"No other global Phase 3 efficacy study has been undertaken during this period with so many variants of concern, including Omicron, and these efficacy data are similar to the recent clinical data from authorized vaccines," said Thomas Triomphe, executive vice president for Sanofi Vaccines.

The companies said they plan to submit the data from their clinical trial to regulators, including the U.S. Food and Drug Administration and the European Medicines Agency. The shots are also currently under a rolling review with the Medicines and Healthcare products Regulatory Agency.

The new Sanofi-GSK shot will rely on a conventional protein-based approach, which is relatively inexpensive to manufacture. Additionally, the shots would likely not require ultracold storage in comparison with Pfizer-BioNTech and Moderna’s mRNA vaccines. The features make the Sanofi-GSK COVID-19 vaccine easier to roll out in nations with low vaccine coverage.

Sanofi and GSK were among the four candidates that received billions of dollars in funding for the development of COVID-19 vaccines under the Trump administration’s Operation Warp Speed initiative.

The firms have lagged behind their rivals in developing the COVID-19 shots after a dosing error early on and disappointing results in producing a strong immune response in older people during its initial clinical trials. The drugmakers also faced setbacks after they struggled to find enough people who have not been infected with COVID-19 to join their clinical trial.