France’s Sanofi and Britain’s GSK said on Friday that their Covid-19 vaccines will not be ready until the end of 2021, after the interim results showed a low immune response in older adults.
The announcement is a major setback in efforts to combat the pandemic, which erupted in China last December and has killed more than 1.5 million people worldwide.
Sanofi and GSK said the delay in their adjuvanted recombinant protein-based COVID-19 vaccine program was to “improve the immune response in older adults.”
The vaccine’s potential availability had been postponed “from mid-2021 to Q4 2021”, they said in a statement.
The American pharmaceutical giant Pfizer and its German partner BioNTech have said that their vaccine has been shown to be 90 percent effective in preventing Covid-19 infections in ongoing phase 3 studies with more than 40,000 people.
The vaccine candidate, developed by Sanofi in collaboration with GSK, is based on technology that Sanofi has used to produce seasonal flu vaccines and on immunological agents developed by GSK.
“Phase 1/2 study interim results showed an immune response comparable to patients recovering from COVID-19 in adults aged 18 to 49 years, but a low immune response in older adults probably due to an insufficient concentration of the antigen,” the statement said. sa.
It is said that a recent study of non-human primates “performed with an improved antigen formulation showed that the vaccine candidate could protect against lung pathology and lead to rapid viral clearance from nasal passages and lungs within 2 to 4 days.
“These results increase companies’ confidence in the capacity of the adjuvanted recombinant platform to deliver a highly effective vaccine for all adults,” it said.
The search for a vaccine raises questions such as whether unexpected safety problems can arise when the number of people vaccinated grows to millions and possibly billions of people.
‘More than one vaccine needed’
It is also unknown whether more side effects will occur with longer follow-up, how long the vaccine will remain effective, whether it will limit transmission and how it will work in children, pregnant women and weakened immune systems.
“We care deeply about public health and that is why we are disappointed with the delay announced today, but all our decisions are and will always be driven by science and data,” said Thomas Triomphe, Executive Vice President and CEO of Sanofi Pasteur.
“We have identified the way forward and remain confident and committed to delivering a safe and effective COVID-19 vaccine,” he said.
Both Russia and China have already launched vaccination campaigns with domestically produced vaccines despite much less control as several other vaccines are being developed in the West.
“No single pharmaceutical company can do it alone; the world needs more than one vaccine to fight the pandemic,” Triomphe said.
Roger Connor, chairman of GSK Vaccines, added: “The results of the study are not what we hoped for. Based on previous experience and other collaborations, we are convinced that GSK’s pandemic adjuvant system, together with a COVID-19 antigen, can produce a robust immune response. “
The companies are planning a phase 2b study which is expected to start in February. If the data are positive, a global phase 3 study can begin in the second quarter of next year.
“Positive results from this study would lead to the submission of legislation in the second half of 2021, delaying the vaccine’s potential availability from mid-2021 to Q4 2021,” the statement said.