People fully vaccinated with the Pfizer-BioNTech vaccine are likely to have more than five times lower levels of neutralising antibodies against the Delta variant, first identified in India, compared to the original strain, according to research published in The Lancet journal.
The study also shows that levels of these antibodies that are able to recognise and fight the virus are lower with increasing age, and that levels decline over time, providing additional evidence in support of plans to deliver a booster dose to vulnerable people.
The study analysed antibodies in the blood of 250 healthy people.
