Delta coronavirus variant is much more likely to cause serious illness and is circulating more rapidly within schools.
Data from Public Health England released on Thursday evening showed that the Delta variant, B.1.617.2, first detected in India, is dominant in the UK, now accounting for 75% of infections.
The Delta variant carried 2.61 times the risk of hospitalisation within 14 days compared with the Alpha variant (B.1.1.7) once demographic factors and vaccination status were taken into account.
He also highlighted what he called “a sort of Nepal mutation”. A mutation of the Delta variant, this is suspected of potentially being more resistant to vaccines.