Omicron Strain Could Reduce Effectiveness of Pfizer Shots by More Than 30 Times - Study

BEIJING (Sputnik) - The Pfizer/BioNTech vaccine could be over 30 times less effective against the Omicron strain of the coronavirus than other variants, a new study reveals.

"The Omicron variant reduced the antibodies of the BioNTech vaccine by at least 32 times," researchers from the University of Hong Kong and Chinese University said in their findings released on Sunday.

According to the new research, conducted using blood samples from ten people, two shots of the Pfizer vaccine proved to have very little neutralizing ability against Omicron. However, a booster shot greatly improves protection, scientists said.

Researchers are now testing the effectiveness of the CoronaVac vaccine, which is also expected to be weaker with respect to the Omicron strain.

A study conducted at Israel’s Sheba Medical Center earlier this month showed that the Pfizer booster’s neutralizing ability against Omicron was four times lower than against Delta. According to the Sheba study, even those who have received two Pfizer shots plus the booster can still get infected with the Omicron variant. People who got the second dose only did not have any protection against Omicron, according to Israeli researchers.

Another study published on the MedRxiv platform showed that two Pfizer doses give 22.5 percent protection against symptomatic infection with the Omicron coronavirus variant.

Pfizer Chief Executive Albert Bourla said this month that his company expected to know within several weeks whether a new vaccine will be needed for the Omicron variant, and doses will likely be available by March.