New COVID-19 vaccine offers 100% efficacy against hospitalization, makers say

Feb. 23 (UPI) -- A new vaccine against COVID-19 offers 100% protection against hospitalization, its makers said Wednesday, and they plan to seek regulatory approval from the Food and Drug Administration and the European Medicines Agency as soon as possible.

The vaccine could be used as an alternative to the currently available products from Moderna and Pfizer-BioNTech, or as a booster for them, they said.

In a recently completed clinical trial of more than 10,000 adults, two doses of the vaccine had "100% efficacy against severe COVID-19 disease, as measured by hospitalizations, according to the manufacturers.

In that phase 3 clinical trial, the last stage of drug and vaccine product research and development, the new Sanofi and GlaxoSmithKline vaccine provided 75% protection against moderate-to-severe COVID-19, they said.

It also gave 58% protection against symptomatic illness following infection, according to the manufacturers.

Although these figures are lower than those initially seen in early clinical trials of the Moderna and Pfizer-BioNTech vaccines, both of which are made using mRNA technology, they are "in line with expected vaccine effectiveness," the companies said in a statement.

This is particularly the case "in today's environment dominated by variants of concern," such as Omicron and Delta, which differ significantly from the version of the virus that causes COVID-19 in circulation at the time the Moderna and Pfizer-BioNTech shots were first developed, they said.

When used as a booster shot following administration of one of the other available vaccines, the Sanofi-GSK product increased antibody levels by 18-fold to 30-fold, they said.

Antibodies are proteins produced by the immune system to fight off viruses, and vaccines are designed to boost their levels in the human body.

Sanofi and GSK had planned to apply for FDA clearance for the vaccine late last year, but delayed the process after earlier clinical trials yielded disappointing results in older adults.

However, the recently completed phase 3 trial tested a stronger version of the vaccine, executives said.

Currently available COVID-19 vaccines target a virus protein called spike, Stephen S. Morse, an expert in emerging infectious diseases, told UPI in an email in January.

The mRNA vaccines from Moderna and Pfizer-BioNTech contain the genetic instructions for making the protein, said Morse, a professor of epidemiology at Columbia University in New York City.

The Sanofi-GSK vaccine uses a slightly modified version of the protein to produce an immune response, a more commonly used approach for vaccines, including the flu shot, executives from both companies said.