COVID-19 vaccine makers Pfizer and BioNTech have begun clinical trials of a new, Omicron-based version of their coronavirus jab, the companies announced on Tuesday.
The US-based study will recruit around 1,400 healthy adults aged 18-55 to help evaluate whether or not there is a need for variant-specific vaccines.
"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 over time and to potentially help address Omicron and new variants in the future," said Kathrin Jansen, Head of Vaccine Research & Development at Pfizer.
Researchers will use the study to compare the new Omicron-based COVID-19 vaccine's safety, tolerability and ability to provoke an immune response to the current formulation, which is the world's most-used COVID-19 vaccine.
Participants in the study will be divided into three groups. Around 600 volunteers who have already had two doses of the regular Pfizer/BioNTech COVID-19 jab will be given one or two boosters of the new formulation.
Another 600 who’ve already received three doses of the standard vaccine will be given a fourth dose of either the regular vaccine or the Omicron-based version.
A third group of people who haven't had any COVID-19 jabs - who Pfizer refers to as "vaccine-naïve" - will be given three doses of the new version.
Vaccine makers have been updating their coronavirus jabs to better match Omicron in case global health authorities decide the change is needed.
While the variant is more likely to cause infection even in people who’ve been vaccinated, it’s not yet clear that a change to the vaccine recipe is needed, as the original vaccines still offer good protection against severe illness and death.
"Vaccines continue to offer strong protection against severe disease caused by Omicron. Yet, emerging data indicate vaccine-induced protection against infection and mild to moderate disease wanes more rapidly than was observed with prior strains," BioNTech CEO Ugur Sahin said in a statement.
Last week, the bosses of Pfizer and competitor Moderna suggested that updated versions of the COVID-19 vaccines would become commonplace in years to come.
Speaking at the World Economic Forum (WEF), Moderna CEO Stéphane Bancel said his company planned to offer a seasonal booster shot that would cover COVID-19 as well as other respiratory illnesses like flu and respiratory syncytial virus (RSV).
"Our goal is to be able to have a single annual booster so that we don't have compliance issues where people don't want to get two to three shots a winter, but they get one dose where they get a booster for corona, a booster for flu and RSV," Bancel told the virtual gathering.