New Covid vaccine 100% effective against severe disease, manufacturers say

French pharmaceutical Sanofi and its British partner GlaxoSmithKline hope their vaccine will also be used as a booster

A new two-dose vaccine developed by French and British manufacturers is 100 per cent effective against severe disease and hospitalisation from Covid-19, the companies have said.

French drugmaker Sanofi and its British partner GlaxoSmithKline fell behind in the race to develop a vaccine, but new data suggest the jab will have a vital role to play in the long-term fight against Covid.

As well as being highly effective in keeping people out of hospital, the vaccine offered 75 per cent protection against moderate-to-severe disease, according to the manufacturers’ phase 3 clinical trial. It also showed 58 per cent efficacy against symptomatic disease.

A second study trial run by Sanofi and GSK found that the jab, when used as a booster dose, increased antibody levels by 18- to 30-fold in people who had already been vaccinated.

The datasets will now be submitted to regulators in the hope of attaining approval. Both trial studies are expected to be published "later this year."

The vaccine relies on a conventional protein-based approach to training the body’s immune system, compared with the newer mRNA technology used in the Pfizer-BioNTech and Moderna shots - both of which have already been rolled out globally.

It is similar in technology to one of Sanofi's seasonal influenza vaccines, and is coupled with GSK's adjuvant, a substance that increases the effectiveness of a shot. It is also easier to store and transport than some rival shots.

The protein technology, which is also behind the recently approved Covid-19 shot from Novavax, has been in use since the mid-1980s, leading public health experts to hope that some of those who have shunned mRNA shots might opt for a vaccine class with a decades-long safety record.

"We are confident that this vaccine can play an important role as we continue to address this pandemic and prepare for the post-pandemic period," said Roger Connor, president of GSK Vaccines.

The vaccine’s 100 per cent effectiveness against severe disease comes at a time in which multiple variants are in circulation, suggesting the shot’s potency is maintained in the face of Omicron, Delta and other strains - unlike many of the other jabs currently in use.

"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 authorised vaccines," said Thomas Triomphe, executive vice president for Sanofi Vaccines.

The companies said they were in discussions for approval of their shot with regulators, including the US Food and Drug Administration and European Medicines Agency.

The head of the Coalition for Epidemic Preparedness Innovations (CEPI), Richard Hatchett, said new protein-based vaccines administered with adjuvants could "potentially become the workforce for vaccinations in the future," when asked about the role of late-comers to the vaccine race.

Whereas the mRNA vaccines contain the genetic instructions for making the spike protein that coats the outside of the Covid virus, the Sanofi-GSK jab uses a modified version of the protein itself to generate an immune response and provide protection.

Sanofi and GSK were expected to seek authorisation for their vaccine last year, but shelved those plans after clinical trials showed disappointing results in older adults. They then developed a stronger version of the vaccine and tested it in new trials.