The companies tested a vaccine that targets the Omicron BA.1 subvariant and a bivalent booster – that targets two strains – that includes the current Pfizer / BioNTech Covid-19 vaccine and a vaccine candidate targeting Omicron.
The study looked at two different dose levels – 30 micrograms and 60 micrograms – in more than 1,200 adults aged 56 years and older. The current primary and booster dose for this age group is 30 micrograms.
The study showed that at both dose levels, the fourth booster with Omicron-modified vaccine candidates resulted in a significantly higher immune response against the variant. One month after injection, the monovalent vaccine showed a 13.5- and 19.6-fold increase in dose-dependent antibodies to Omicron. The bivalent vaccine showed a 9.1 and 10.9-fold increase in antibodies.
Preliminary results from laboratory studies also suggest that the vaccines may neutralize Omicron BA.4 and BA.5, the companies said. BA.4 and BA. 5 sub-options are increasingly prevalent in the United States.
Both vaccine candidates appear to be safe and well tolerated.
The results have been shared in a news release and have not yet been reviewed or published.
“Based on these data, we believe we have two very strong Omicron-modified candidates that elicit a significantly higher immune response against Omicron than we’ve seen before,” Pfizer Chairman and CEO Albert Burla said in a press release.
Earlier this month, Moderna reported that its divalent booster for the Covid-19 vaccine, which contains a vaccine targeting Omicron, showed a stronger immune response against the variant. The company said its updated booster also showed a “powerful” response against sub-options BA.4 and BA.5. The companies will present their data on Tuesday when the US Food and Drug Administration’s Advisory Committee on Vaccines and Related Organic Products meets to vote on updated coronavirus vaccines for the fall.
Add Comment