One of the 23 people known to have contracted the Bristol coronavirus variant had been vaccinated just a few days earlier, according to an official report.
A Public Health England briefing published on Saturday (February 13) states that one of the cases arose five days after the person was vaccinated, potentially meaning they were only days away from some level of immunity.
Public Health England has stressed the importance of vaccination to protect people against severe illness and death from all variants of Coronavirus. Analysis of 18 of the mutated cases also showed that none had led to death or hospital treatment.
While some doubts have been raised about the level of effectiveness of the vaccine against the Bristol variant, it is important to stress that this case does not corroborate those concerns.
This is because even if the person had the Pfizer vaccine, which is thought to offer protection slightly more quickly than the Oxford jab, research suggests it takes 10 days to develop a good level of protection after the first dose.
The PHE report states: “Of 23 cases, data are available for 18, of which one was known to be vaccinated before the onset of infection (5 days prior).”
Five days would likely not have been enough time for the immune system to generate a response to the vaccine.
It is also possible the person already had the virus before vaccination, as it can take days for symptoms to show.
The case is a reminder of why people have been urged to continue to adhere to social distancing and lockdown rules, even if they have been vaccinated.
Although Public Health England acknowledged last week that the mutation could have “some impact” on the vaccine, research suggests that the vaccines currently being used “are highly likely to give strong protection against severe disease”.
A spokesperson told Bristol Live: “Although there is currently no evidence this mutation alone causes more severe illness or greater transmissibility, it is reported to result in weaker neutralisation by antibodies in laboratory experiments.
“This could have some impact on the efficacy of a vaccine and we’re studying this closely.
“Importantly though, recent studies show the vaccines we are now deploying are effective against the dominant variants in the UK.
“Both the Pfizer and Oxford vaccines are highly likely to give strong protection against severe disease and death, regardless of the variant.
“These are the outcomes that matter most and are what will prevent people from ending up in hospital.”
Bristol’s variant, known as VOC 202102/02, is the widespread Kent variant with an additional mutation known as E484K.
The same report published on Saturday revealed that it has been present in the Bristol area since before Christmas.
It also noted there are several known clusters of the variant – the majority in the Bristol area, plus six cases outside of the South West.
The last known case as of February 11 was from a test on January 31, which would suggest that the surge testing programme currently under way in the area has not yet identified any new cases.
Numbers ‘could underestimate’ spread
However, the report notes a time lag and advises: “The current number of confirmed cases with this mutation may be underestimated.”
Discussing why the Bristol variant is of concern, it continues: “E484K is a mutation of concern with regards to antigenic change and receptor binding avidity, and is potentially more concerning when combined with N501Y [the mutation present in the Kent variant].
“E484K is currently the mutation with most evidence of causing antigenic change.
“Several independent studies showing the impact of different antigenic variants have concluded E484K is among the single mutations with the greatest impact.”