The CEO of Pfizer on Monday said it’s not clear if a fourth dose of his company’s COVID-19 vaccine is necessary, but predicted that an Omicron specific version of the shot would be available by March.

Albert Bourla told CNBC that more evidence was needed on a fourth dose before it is known whether it offers more protection from the coronavirus, even though Israel is already two weeks into a campaign to distribute extra boosters to the elderly, at-risk, and medical workers.

“I don’t know if there’s a need for a fourth booster, that’s something that needs to be tested, and I know Israel has already started some of these experiments and we will also conduct some of these experiments to make sure that if needed, we use it,” Bourla said.

“I don’t think we should do anything that is not needed.”

Following the emergence of the Omicron variant of coronavirus, which has shown an ability to break through other vaccine defense, Israel started offering fourth vaccine shots to people 60 and over, medical workers and those who are immunosuppressed.

Last week, Prime Minister Naftali Bennett said the fourth Pfizer-BioNTech dose causes a significant boost in antibodies within a week after taking it, citing interim data from Israel’s study on the matter among medical workers at one hospital.

Since the trial at Sheba Medical Center began in late December, there is no data on whether the number of antibodies maintains itself over time after the first week, or whether the antibodies provide better protection against catching — or developing serious illness from — Omicron.

Sheba’s trial program, which began with 150 medical staff being given the shot, is many times smaller than normal drug trials, which usually involve thousands of volunteers whose results are tracked for months. But it is also the only known study of the effects of a fourth dose, with Israel pinning hopes that the extra booster may help keep the variant from overwhelming hospitals and shutting down normal life.

National coronavirus czar Salman Zarka has acknowledged that little is known about the fourth dose, but urged those eligible to get it anyway.

As of Sunday, over a quarter million Israelis were reported to have received a fourth vaccine dose.

Chile on Monday joined Israel in distributing fourth shots. The country is only giving the shot to immunocompromised until early February, when it will open to those age 55 and older .

Bourla did not specify if his reservations over administering a fourth dose of the current vaccine was due to Pfizer’s development of a shot adapted to Omicron, which he said the United States pharmaceutical firm will soon be ready to widely distribute.

“This vaccine will be ready in March,” he said in the CNBC interview. “We [are] already starting manufacturing some of these quantities.”

“The hope is that we will achieve something that will have way, way better protection particularly against infections, because the protection against the hospitalizations 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 added.

Bourla first announced in November that Pfizer was working on a vaccine against Omicron, which studies have indicated is better able to evade the protection from vaccines than previous coronavirus strains.

Pfizer has said its vaccine is “still effective” against Omicron after three doses.

Other COVID vaccine makers have also started working on updating their shots amid signs they are less effective at protecting against Omicron.

Source: TOI