A Covid-19 vaccine developed by
and GSK PLC to target the Beta strain of the virus produced a stronger antibody response against variants of Omicron when given as a booster compared with certain first-generation shots, two studies have found.
The results are the latest indication that tweaking vaccines can nudge antibody responses in the direction of new variants, possibly helping to shore up immunity as the virus mutates. The study results may also provide an opportunity for Sanofi and GSK, two vaccine giants that were late to develop Covid-19 immunizations, to play a role in providing booster shots.
In the studies, the Beta-targeted vaccine induced a stronger antibody response to certain Omicron variants than both the original Sanofi-GSK shot and the vaccine produced by
Neither study has yet been peer-reviewed.
In a study comparing a booster of the Sanofi-GSK Beta-targeted vaccine with the companies’ original shot, the tweaked vaccine induced double the number of neutralizing antibodies against Omicron BA.1 and BA.2 than the older version, Sanofi said Monday. The study, run by the companies, involved around 1,500 people who had received either the Pfizer or
vaccines as their primary course of vaccination.
A separate, smaller study run by French researchers compared the Beta-variant Sanofi-GSK vaccine to either the older Sanofi-GSK shot or the Pfizer vaccine as a booster in people who had received two doses of the Pfizer shot. It found that a booster of the Beta-variant shot produced higher levels of neutralizing antibodies against the Omicron BA.1 variant than either of the other two. That study, which involved 247 people, was funded by the French government and Sanofi.
Both studies measured the immune responses of participants two weeks after receiving the vaccines. They didn’t examine whether the various shots reduced the risk of Covid-19 disease caused by Omicron.
head of vaccines at Sanofi, said the Beta variant shared some mutations with multiple variants of concern, including Omicron, making it a strong vaccine candidate to provide broad protection against various strains of Covid-19. The Beta variant circulated for several months after it was first identified in South Africa in the fall of 2020 but faded away as the Delta variant became dominant in mid-2021.
The Sanofi-GSK vaccine combines a synthetic version of the virus’s spike protein, manufactured by Sanofi, with Glaxo’s adjuvant, a substance used in some vaccines to enhance the immune response. In the original version, the spike protein was based on the original strain, whereas in the newer shot, it was based on the Beta variant. The approach, similar to that used by
is widely used against other diseases, including in some routine childhood immunizations such as hepatitis B.
The highly-contagious Omicron variant became the dominant strain of Covid-19 over the winter and has been able to get around some of the protection conferred by the original vaccines because of mutations in the spike protein targeted by the shots. The rapid rise of Omicron prompted vaccine makers such as Moderna and Pfizer to design and start testing shots that take aim at the strain, in the hope of spurring a stronger immune response to the new variant than the first-generation vaccines.
Last week, Moderna said that its modified shot produced a stronger antibody response against Omicron than its original shot, when given as a booster. Moderna’s new shot is designed to target both the original strain and the Omicron variant.
Pfizer and partner BioNTech are also expected to soon release study results on their Omicron-targeting shot.
When scientists first developed variant vaccines for Covid-19, they were unsure whether they would trigger a stronger immune response to variants of concern than boosting with the original shots.
U.S. health officials are considering whether modified booster shots targeting variants should be used for a fall vaccination campaign.
Sanofi and GSK, two of the world’s largest vaccine makers, fell behind in the race to develop shots against Covid-19, but say their technology could play a role as a booster. The companies’ original shot, against the original strain of the virus, is still under review by regulators. The companies said they planned to submit the new data relating to the Beta variant vaccine in coming weeks, with the aim of making it available later this year.
Write to Denise Roland at [email protected]
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