Health Secretary Sajid Javid has warned of the potential threat of future coronavirus variants as he urged people to get vaccinated and take up the offer of a booster jab.
Downing Street said this week it was monitoring the AY4.2 variant – a descendant of the coronavirus Delta variant that is being seen in a growing number of cases – but insisted there was no evidence it spreads more easily.
Mr Javid said that Covid-19 mutates, like any virus, adding that new variants are being identified “all the time”.
“This includes a new version of the Delta variant, which is currently known as AY4.2, and that new variant is now spreading,” he told a Downing Street press briefing.
“And while there’s no reason to believe at this point that AY4.2 poses a greater threat, the next variant, or the one after that, might do.
“So we need to be ready for what lies around the corner. This means our ongoing programme of booster jabs is so important, and this winter we’re prioritising those most in need.
“Today we’ve reached a milestone of 4 million top up jabs in England, but we need to get even more people protected.
“We’ve got the jabs, we just need the arms to put them in.”
Scientists say AY4.2 carries two characteristic mutations in the spike, Y145H and A222V, both of which have been found in various other coronavirus lineages since the beginning of the pandemic.
However, they have remained at low frequency until now.
The first strains carrying both mutations were sequenced in April 2020, and either are found in any variant of concern.
AY4.2 is rare outside the UK, and there have been only three cases detected in the US so far.
In Denmark, the other country that, besides the UK, has excellent genomic surveillance in place, it reached a 2% frequency but has gone down since.
Work is under way to test whether it may be less well recognised by antibodies.