Early laboratory indicates that three doses of the Pfizer vaccine provide as much protection against the variant as two shots did against the original Covid virus.
Scientists assessed blood from individuals who had received only two doses and found there was a 25-fold reduction in antibody levels against the variant.
However, the blood samples obtained from people one month after they had been boosted showed far higher levels of antibodies, raising hope that those who have received three doses will remain protected against omicron.
There was also nothing to suggest that T cells generated by vaccination — another key part of the immune system’s response — are significantly weakened by the variant. That suggests “vaccinated individuals may still be protected against severe forms of the disease” after only two doses, Pfizer said.
Pfizer announced the early lab data in a press release and it has not yet undergone scientific review.
However, the findings are broadly in line with a preliminary study published by researchers at the Africa Health Research Institute in South Africa on Tuesday, saying that Omicron can partially evade protection from two doses of the vaccine, suggesting also that a third shot might help fend off infection.
“Ensuring as many people as possible are fully vaccinated with the first two dose series and a booster remains the best course of action to prevent the spread of Covid-19,” Pfizer boss Albert Bourla said in a statement.
Though the necessity remains unclear, Pfizer and its partner BioNTech said they would continue their efforts to develop an omicron-specific vaccine.
More to follow