Omicron Variant Two Doses Of Pfizer Vaccine ‘May Not Stop Infection'

Three doses of the Pfizer/BioNTech vaccine are likely to protect against infection with the Omicron variant but two doses may not, according to data that will increase pressure to speed up booster programmes.

- Hannah Devlin

Tests using antibodies in blood samples have given some of the first insights into how far Omicron escapes immunity, showing a stark drop-off in the predicted protection against infection or disease for people who have had two doses. The findings suggest that, for Omicron, Pfizer/ BioNTech should now be viewed as a three-dose vaccine.

The vaccine makers said they would continue at full speed with plans to develop an updated Omicron-based vaccine by March 2022.

Separate results, from preliminary studies by the German Center for Infection Research, also found significant reductions in antibody potency for Pfizer/BioNTech, Moderna and Oxford/AstraZeneca vaccines.