The fast-spreading new variants of the Omicron strain of COVID have evolved to evade human immune system responses, according to a new scientific study.
German researchers tested therapeutic antibodies and also human plasma on strains of the Omicron virus – and found that in many cases B.4 and B.5 strains, now common in the UK, were much less vulnerable than other strains.
They conclude that B.4 and B.5 are becoming the dominant strain because of their ability to evade the immune system rather than because of increased infectivity.
The variants are driving an increase in hospitalisations in the UK – although there is little sign of numbers of deaths increasing.
The researchers, at the Leibniz Institute for Primate Research and Hanover Medical School, found that only one antibody, Bebtelovimab, efficiently blocked infection by all Omicron variants. They reported their findings in the *Lancet Infectious Diseases*.
Researcher Prerna Arora said: “These results confirm a trend that we have already seen in previous studies: Omicron subvariants are not appreciably inhibited by most therapeutic antibodies and the few antibodies that inhibit frequently do so in a subvariant-specific fashion. Therefore, it is important to develop new antibodies in order be prepared for future subvariants.”
Fellow researcher Markus Hoffmann said: “BA.2.12.1 and particularly BA.4 and BA.5 are antibody evasion variants. Vaccination will still protect against severe disease induced by these variants but protection might be somewhat less efficient as that measured for previously circulating variants.”
Augmented neutralisation resistance of emerging omicron subvariants BA.2.12.1, BA.4, and BA.5. *Lancet Infectious Diseases* 28 June 2022
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