Coronavirus: Omicron protection should be effective after three doses, say Pfizer-BioNTech
- Early tests show vaccine effective in preventing Covid-19, and against Omicron, if given three times; but warn variant not ‘sufficiently neutralised after two doses’
- Follows other preliminary results from a study in South Africa suggesting a 40-fold drop in ability of antibodies from Pfizer-BioNTech vaccine to neutralise Omicron
Omicron has caused global concern over signs that it can transmit faster than previous strains and fears that its multiple mutations could help it evade immune defences provided by vaccines. No deaths have yet been associated with the variant.
In preliminary results published on Wednesday, Pfizer and BioNTech said their vaccine “is still effective in preventing Covid-19, also against Omicron, if it has been administered three times”.
But they warned that “the Omicron variant is probably not sufficiently neutralised after two doses”.
According to the early laboratory research using blood serum from vaccinated people, a booster third dose generated around the same level of antibodies against Omicron as is seen after a second dose with other variants.
Blood samples from people who had received two doses of the current vaccine showed on average a 25-fold reduction in neutralising antibodies compared to the early strain of the virus, the companies said.