New York, Jan 11 (IANS): Pfizer's vaccine that specifically targets the Omicron variant of Covid-19 will be ready in March, the pharmaceutical giant's CEO Albert Bourla has said.

Bourla said Omicron is a more difficult target than the previous variants, CNBC reported.

Omicron, which has more than 30 mutations on its spike protein, can evade some of the protection provided by Pfizer's original two shots.

While it is still unclear whether or not an Omicron vaccine is needed or how it would be used, he added that the company will have some doses ready since some countries want it ready as soon as possible.

The vaccine will also target the other variants that are circulating, Bourla said adding that the US-based drug maker has already begun manufacturing.

"This vaccine will be ready in March," Bourla told CNBC's "Squawk Box". "We (are) already starting manufacturing some of these quantities at risk."

Bourla also emphasised the importance of a third shot to boost people's protection against Omicron.

He said that the two-dose vaccine does not provide robust protection against infection and its ability to prevent hospitalisation has also declined.

"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," Bourla said.

Real-world data from the UK has shown 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, according to study from the UK Health Security Agency.

However, the original two doses still provide good protection against severe illness, the study found. Booster shots are up to 75 per cent effective at preventing symptomatic infection, according to the study.

Earlier, the US' top infectious disease expert Anthony Fauci has said that there is no need for a booster shot that specifically targets Omicron, because the current boosters work well against the variant.

Meanwhile, Moderna is also working on a booster that targets Omicron.

CEO Stephane Bancel said the company will soon enter clinical trials, adding that the demand is high from governments as they prepare regular vaccination against the virus.