A Covid-19 vaccine made by French lab Sanofi with British pharmaceutical giant GSK could be available by the end of the year, after the results of Phase 2 clinical trials were this week judged as “excellent”.
Yesterday (May 17), the group published the results of its trials on 722 volunteers aged 18 and over in the US, Honduras, and Panama.
Should results continue to be successful, the vaccine could be available to the public by the end of 2021.
How does the Sanofi-GSK vaccine work?
The technology works using ‘recombinant proteins’; the same technology that is already used for flu vaccines.
The active protein in the virus (the ‘S’ or Spike protein) normally works as a ‘key’ to the body, allowing the virus to spread through the body’s cells. This vaccine technology seeks to replicate a similar kind of protein, which, when injected into the body, prompts the immune system to create antibodies that would be effective against the real virus, by neutralising its S protein.
Without this protein, the virus cannot enter the body’s cells, and therefore cannot spread.
The protein alone is not enough to prompt the immune response, however.
The vaccine works on the ‘adjuvanted-antigen’ principle, which introduces the antigen into the body, along “with an ‘adherent’ [or an 'adjuvant'] that will send an alarm signal to the immune system”, research director Bruno Pitard explained to CNRS Le journal.
He said: “A protein alone, even if it is a viral protein, will not be considered dangerous by the body, which produces billions of [proteins] itself. It must therefore be signalled to the immune system.”
Vaccines that work on this S protein principle are relatively stable, and can be stored at temperatures of 2-8C, making them easier to transport and store than vaccines that require super deep-freeze conditions.
What are the results of the latest clinical trial?
The results of the Phase 2 trials – on human volunteers – have been judged as successful.
In a press release, the company said that the vaccine “induces the production of high levels of neutralising antibodies in adults of all ages at levels comparable to those seen in people who have recovered from [Covid] infection”.
The vaccine was found to create antibodies in 95-100% of cases after the administration of two doses, on all age groups tested, from age 18 to 95.
Sanofi said that for participants who had already had Covid, only one injection of the vaccine was needed to create the same level of antibodies. “This underlines the solid potential interest that its development represents for the booster vaccine”, Sanofi said.
Phase 3 of the trials – the final phase before potential authorisation for wider use – is set to start in the next few weeks. Sanofi is set to begin production of the vaccine at the same time, in the hope that it will be on the market by the end of 2021.
Today we announced positive results of the Phase 2 trial of our #COVID19 recombinant #vaccine candidate developed with @GSK. We can now progress to Phase 3, bringing us another step us closer to protecting people against this virus. https://t.co/nP5cH6PJZ6#SanofiActs pic.twitter.com/BWG0r8asyq— Sanofi (@sanofi) May 17, 2021
Will this new Sanofi-GSK vaccine be effective against new virus variants?
This is unclear for now. The vaccine has been tested against the original variant and the South African variant, but not the UK or Indian strains.
Frédéric Bizard, health economist, and president of the Institut Santé, was sceptical that this vaccine will be truly effective against the new strains.
He told FranceInfo: “This is one of [this vaccine’s] limitations. We have a vaccine here that is ‘first generation’, and which will basically have a complementary role when it comes to protecting the population.”
Why is this vaccine so ‘behind’ compared to the other vaccines on the market?
The vaccine development was delayed after an initial study in late 2020 showed that it did not produce enough of an immune response in people aged 50 and over.
The lab was forced to push the potential launch of its vaccine to the final quarter of 2021, pending further development and trials.
In an interview with the Wall Street Journal in December 2020, Thomas Triomphe, Sanofi’s executive vice president for vaccines said that the initial trials had failed due to “a mistake”, and that “volunteers were accidentally given lower doses than intended in initial clinical trials due to a miscalculation in the manufacturing process”.
He said that Sanofi would need to “reformulate the vaccine to fix the problem”, and admitted that it was “a sad setback”.
But, he said: "We prefer to take a step back, let the science work and come back with a product that is very effective in addition to being safe...You don’t want to make compromises there.”
On January 26, economic council Le Conseil d’analyse économique published a damning report, highlighting France’s “significant delay” in the pharmaceutical innovation sphere, and said that the only solution would be to “increase the public money allocated to fundamental research”.
It also recommended that France increase researchers’ starting salaries, after it found that they were 63% lower than the average for countries in the Organisation for Economic Co-operation and Development (OECD).