Pfizer and BioNTech start trial of Omicron-specific vaccine

Pfizer and BioNTech have started a clinical trial to test a new version of their vaccine specifically designed to target the Omicron variant of Covid-19, which has eluded some of the protection provided by the original two-dose vaccine regimen.

The companies plan to test the immune response generated by the Omicron-based vaccine both as a three-shot regimen in unvaccinated people and as a booster shot for people who already received two doses of their original vaccine.

They are also testing a fourth dose of the current vaccine against a fourth dose of the Omicron-based vaccine in people who received their third dose of the Pfizer/BioNTech vaccine three to six months earlier.

The companies plan to study the safety and tolerability of the shots in the more than 1,400 people who will be enrolled in the trial.

“While current research and real-world data show that boosters continue to provide a high level of protection against severe disease and hospitalisation with Omicron, we recognise the need to be prepared in the event this protection wanes and to potentially help address Omicron and [possible] new variants,” Kathrin Jansen, Pfizer’s head of vaccine research & development, said in a statement.

Pfizer has said that a two-dose regimen of the original vaccine may not be sufficient to protect against infection from Omicron, and that protection against hospitalisations and deaths may be waning.

Still, the US Centers for Disease Control and Prevention says a third dose of an mRNA vaccine like the Pfizer/BioNTech vaccine has provided 90% protection against hospitalisation due to Covid-19.

Some countries have already started offering additional booster doses, but a recent study from Israel shows that while a fourth dose of an mRNA vaccine boosted antibodies, the level was not high enough to prevent infection by the Omicron variant. 

Reuters