Already, there are small changes in the virus that have appeared independently several times around the world, suggesting that the mutations are useful to the pathogen. The mutation affecting antibody sensitivity – technically called the 69-70 deletion, which means letters are missing in the genetic code – has been seen at least three times: in Danish minks, in the British and in an immunocompromised patient who has become much less sensitive to convalescent plasma.
“This thing transmits, it acquires, it adapts all the time,” said Dr Ravindra Gupta, a virologist at the University of Cambridge, who last week detailed the recurrent emergence and spread of suppression. “But people don’t want to hear what we’re saying, which is this virus is going to mutate.”
The new genetic suppression alters the spike protein on the surface of the coronavirus, which it needs to infect human cells. Variants of the virus with this deletion independently emerged in Thailand and Germany in early 2020 and became widespread in Denmark and England in August.
Scientists initially believed the new coronavirus was stable and likely would not escape the vaccine-induced immune response, said Dr Deepti Gurdasani, clinical epidemiologist at Queen Mary University in London.
“But it has become very clear over the past few months that mutations can occur,” she said. “As the selection pressure increases with mass vaccination, I think these mutants will become more common.”
Several recent papers have shown that the coronavirus can evolve to avoid recognition by a single monoclonal antibody, a cocktail of two antibodies, or even convalescent serum given to a specific individual.
Fortunately, the whole body’s immune system is a much more formidable opponent.
The Pfizer-BioNTech and Moderna vaccines induce an immune response only to the spike protein carried by the coronavirus on its surface. But each infected person produces a large, unique and complex repertoire of antibodies against this protein.