ATLANTA (CNN) – A mutation that could allow COVID-19 to escape antibody protection has been found in samples from a rapidly spreading strain in the UK, according to a report released Monday by Public Health England.
The mutation, called E484K, was already part of the genetic signature of variants related to South Africa and Brazil.
According to the PHE report, the mutation has recently been detected in at least 11 samples from strain B.1.1.7 in the UK. It also appears that some of these samples may have acquired this mutation independently, rather than propagating from a single case.
This could mean that a variant that is already known to be more transmissible and also runs the risk of slightly resisting the immune protection offered by vaccines, or is more likely to cause reinfection among people who were previously infected, according to experts.
“This doesn’t seem like great news for vaccine efficacy,” said Joseph Fauver, an associate researcher in epidemiology at the Yale School of Public Health.
He added that the new finding is also something that needs to be further monitored in the United States, where efforts to look for variants through genetic sequencing have lagged behind the UK. The fact that we’ve only seen it in the UK “may be the result of its genomic surveillance program,” Fauver said.
Evidence of immune leakage
Experts say it is too early to predict whether this development will greatly affect the trajectory of COVID-19 in the UK and around the world.
However, there is some research suggesting that E484K may be one of the main reasons why some vaccines seem less effective in South Africa.
Novavax recently announced that its vaccine was 89% effective in its Phase 3 trial in the UK, but only appeared 60% in a separate Phase 2b study conducted in South Africa. Similarly, in the Johnson & Johnson phase 3 trial, efficacy differed by country: 72% in the U.S. versus 57% in South Africa. In both trials, 90–95% of cases in South Africa were related to variant B.1.351, which contains the E484K mutation.
But much of the first evidence for this so-called “escape mutant” comes from research in the lab, which shows that antibodies appear to be less able to bind spike proteins derived from the mutation.
The latest example comes from a new study that found that vaccinated people’s antibodies were less effective at neutralizing a synthetic virus similar to those in the PHE report, i.e., they contained fundamental mutations in B.1.1.7, more E484K.
The addition of the E484K mutation appeared to increase the level of antibodies needed to prevent the virus made in the laboratory from infecting cells, compared to B.1.1.7 mutations.
The study took blood samples from 23 people who had received a single dose of the Pfizer / BioNTech vaccine three weeks earlier, with a mean age of 82 years. The study was unable to show how this affected people’s actual likelihood of becoming infected with virus variants.
Citing the GISAID genomics database, the study also had a slightly higher total number of cases than in the PHE report: two unrelated cases in Wales and a group of more than a dozen in England, which they already appeared in the first fortnight of December 2020.
The most important vaccines ever
Paul Bieniasz, a virologist at Rockefeller University, noted that the E484K mutation has appeared “sporadically” in several samples for months, but until recently did not appear to offer the virus an advantage in populations without preexisting immunity.
But it’s a different story in places like South Africa, where a lot of people had previously been infected. On Monday, Dr Anthony Fauci noted “a very high rate of reinfection to the point that the previous infection does not appear to be protecting itself”, citing the work of South African colleagues.
The B.1.1.7 strain first detected in the UK has now been found in at least 70 countries around the world, including some 470 known cases in the US, according to the US Centers for Disease Control and Prevention.
Experts say aggressive testing, compliance with COVID-19 guidelines and rapid deployment of vaccines are more important than ever in light of these spread variants.
“We need to vaccinate as many people as we can,” Fauci said earlier. “While there is diminished protection against variants, there is enough protection to prevent you from suffering serious illness, including hospitalizations and deaths.”
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