Up to three-quarters of new UK Covid cases are thought to be caused by the variant first detected in India, as the reported number more than doubled to almost 7,000, Matt Hancock said on Thursday.
The variant, known as B.1.617.2, is now dominant in the UK and has been linked to a rise in cases in hotspots around the country. Data released on Thursday by Public Health England (PHE) shows 6,959 cases have been confirmed so far in the UK, up from 3,424 the week before.
Meanwhile, experts said the link between Covid cases and hospital admissions had been greatly weakened but not broken. Speaking in the Commons on Thursday, the health secretary said Covid cases were now at their highest level since 12 April, with 3,180 reported in the UK on Wednesday, but thanks to vaccinations the “link from cases to hospitalisations and to deaths is being severed”.
But experts say the link is not yet broken because only 44% of adults have received both Covid jabs and the vaccines do not offer 100% protection against hospitalisation. “You can see that in Bolton but you can see [it] most clearly in Scotland,” said Prof Christina Pagel, director of UCL’s clinical operational research unit.
Scotland, which has seen outbreaks of the India variant in areas including Glasgow, had 98 patients in hospital with Covid on 26 May, up from 58 on 6 May.
Meanwhile Bolton NHS foundation trust, which serves an area also hard-hit by the India variant, has seen the number of patients in hospital rise from 11 on 9 May to 41 on 25 May – the latest date for which figures are available.
According to Hancock, around one in 10 people in hospital in current Covid hotspots has had both jabs, noting this suggests that we can have a “high degree of confidence” that the vaccines are very effective.
Paul Hunter, professor in medicine at the University of East Anglia, said a link between cases and hospitalisations remained. “If case numbers go up hospitalisations will inevitably go up,” he said. “The issue is whether they go up as far as was the case in the past and that is probably a no.”
“At present [it is] difficult to give an exact ratio [as it] depends on [the] protective effect of [the] vaccine and the demographic of most cases,” Hunter added, noting that in Bolton the majority of cases at present are in younger people.
A new report from PHE also suggests the link has not yet been broken. “Case rates increased slightly in most regions, and in all age groups and ethnic groups,” the report says, adding that rates were highest in those aged 10 to 19 and in north-west England.
But hospital admission rates for Covid also showed a small rise, with a rate of 0.79 per 100,000 compared with 0.75 per 100,000 in the previous week. Rates were highest in the West Midlands and among those aged 85 and above.
Even once the vaccination programme is complete, experts have warned a surge in cases could lead to a large rise in hospital admissions, with modelling suggesting many of those who would be hospitalised in a future third wave are likely to have been fully vaccinated but to have not received good protection from the jabs.
“If you get infections high enough, even the small percentage of people who get sick after two vaccines is enough to overwhelm the NHS,” said Pagel.
