Pfizer's CEO says a Covid-19 vaccine targeting the Omicron variant is likely to be ready in March.
"This vaccine will be ready in March," Albert Bourla told CNBC. "We [are] already starting manufacturing some of these quantities at risk."
Bourla said the new vaccine production was instigated due to keen interest from authorities, as governments across the world contend with huge Covid-19 infection counts, including large numbers of "breakthrough" Omicron cases in vaccinated populations.
"I don't know if we will need it," he said. "I don't know if and how it will be used."
Bourla said the vaccine will also target the other variants. He added that the existing regime of two Pfizer vaccine shots and a booster has provided "reasonable" protection against Omicron.
"The hope is that we will achieve something that will have way, way better protection particularly against infections, because the protection against the hospitalisations and the severe disease - it is reasonable right now, with the current vaccines as long as you are having let's say the third dose," he said.
A study from the UK shows that Pfizer's and Moderna's vaccines are only about 10 per cent effective at preventing symptomatic infection from Omicron 20 weeks after the second dose. However, the original two doses still provide good protection against severe illness, the study found. Booster shots are up to 75 per cent effective.
US chief medical advisor Dr Anthony Fauci said in December that there is no need for a booster shot that specifically targets the new variant, because the current boosters work well.
The highly contagious Omicron variant has sent new cases of Covid-19 exploding worldwide.
Over the past month, the US and UK have recorded the highest number of new cases of the virus in the world, according to data from Johns Hopkins University.
Meanwhile, infections in Australia have surpassed one million, more than half in the past week alone, throwing a strain on hospitals and supply chains.
In a separate interview on CNBC, Moderna CEO Stephane Bancel said the company is developing a booster that could address Omicron and other emerging strains.