Why haven’t there been any more Covid variants recently?

Q Are there no more new variants?

A The UK has not seen a new variant of the coronavirus for quite some time now.

This is because the Delta variant – initially dubbed the Indian variant – which first arrived in the UK in March, is far more infectious than any other.

Viruses mutate all the time, constantly forming new variants. Most of the time, these variants change very little about how the virus acts. But occasionally new mutations can give the virus an advantage, making it more likely to transmit, for example, or more resistant to vaccines.

At the time of the Delta variant’s arrival, health officials were concerned about a number of variants, particularly the Kent (Alpha) variant, which emerged before Christmas, and was partly blamed for the surge in cases and subsequent lockdown, and the South African (Beta) variant, which scientists believed the vaccines were less effective against.

However, because Delta is so much more contagious than other variants – 64 per cent more so than its closest rival the Kent variant – it has effectively killed off all other variants in the UK.

According to data from the UK Health Security Agency, Delta accounts for more than 99 per cent of all Covid infections in Britain – a pattern that hasn’t changed since July.

While the infectiousness of Delta is in large part responsible for the high number of infections the UK continues to record, scientists argue it is good news that the variant remains dominant.

This is because studies have shown the vaccines are effective at significantly reducing the risk of hospitalisation and death from the Delta variant.

However, scientists have pointed out that Delta itself is mutating, and five ‘subtypes’ have now been identified.

One of those subtypes – called AY.4 – now accounts for almost 80 per cent of all Delta cases and there are suggestions that it could be ten per cent more infectious than the original Delta variant.

Thankfully, Professor Christina Pagel, director of University College London’s Clinical Operational Research Unit, argues this is a ‘very moderate advantage’ and says there is no suggestion that any Delta subtype was more resistant to vaccines.