The variants give no respite to vaccines. Now under observation is Pfizer which appears to be ineffective against the Indian variant, now called the Delta variant according to the new nomenclature introduced by the World Health Organization (WHO). Antibodies produced by people who have received both doses of the Pfizer / BioNTech vaccine tend to be more than five times less effective against the B.1.617.2 Delta variant than they are against the original version of the SarsCoV2 virus. This is indicated by the research conducted in Great Britain, with the coordination of the Francis Crick Institute and published in The Lancet journal. Coordinated by Emma Wall and David Bauer, both of the Francis Crick Institute, the research indicates that the level of antibodies becomes lower with increasing age and tends to decline over time.
The researchers measured the level of neutralizing antibodies and their effect on major variants of the SarsCoV2 virus in 250 individuals aged 33 to 52, some of whom had received one dose of the Pfizer-BioNTech vaccine and two others. The research was conducted in the context of the British Legacy study, launched in January and conducted by University College London and the Francis Crick Institute with the aim of tracing the serological responses to vaccination against the Delta variant, which has now become dominant in Great Britain, where it replaced the English variant B.1.1.7 (Alpha). For the authors of the study “it is difficult to accurately assess to what extent the reduction of antibodies will have an impact on the efficacy of the vaccine”, just as it is difficult to predict the effects on “the severity that the disease could have in a vaccinated population” .