Hospital cases continue to rise, with the latest data showing a 37 per cent increase week on week.
According to the figures, the North West saw the largest increase on Monday, with a 56 per cent growth.
The Covid Actuaries Response Group has estimated the current “R” value for the virus, meaning the rate one person infects others, is 1.18.
The expert group said its recent analysis suggested deaths of patients with Covid in English hospitals may now be increasing, adding “it is clear at least that they are no longer decreasing.”
It comes amid global concern over the two new sub-variants of Covid-19, known as BA.4 and BA.5.
The World Health Organisation has been investigating two Omicron sub-variants since April to assess whether they are more infectious or dangerous than their predecessor. Both BA.4 and BA.5 have been added to the agency’s monitoring list.
Moderna has meanwhile announced that its variant vaccine — created specifically to tackle the Omicron variant of the virus which causes Covid-19 — generates a “high” and “strong” antibody response against BA.4 and BA.5.
“We think this is a strong, powerful antibody response, it is probably long lasting,” Dr Paul Burton, Moderna’s chief medical officer, told reporters on Wednesday.
He said that the firm’s variant vaccine could be a “turning point” in the fight against Covid-19 which could “allow us for the first time to get to get ahead of this virus”.
He added that the BA.4 and BA.5 subvariants were “more pathogenic” with a higher risk of hospital admission than the original Omicron strain.
Dr Burton pointed to data from South Africa where hospital admissions appear to have been higher when BA.4 and BA.5 were the dominant strains compared to the original Omicron variant.
He also pointed to studies which have suggested that the sub variants are better at causing lower lung infections compared to the original Omicron strain — which was more likely to cause sore throats and runny noses. Lower lung infections could lead to a spike in pneumonia cases.
Dr Burton said younger adults and children should be eligible for booster jabs in the autumn, and warned that people could be “under-protected and under-vaccinated” without a wider booster programme.
Vaccination advisers in the UK have said that over 65s, frontline health and social care workers, older care home residents and adults aged 16 to 64 years “in a clinical risk group” should be invited for an autumn booster.
Last week, new figures showed that Covid-19 infections in the UK increased by 43 per cent in the week after the platinum jubilee celebrations, with BA.4 and BA. believed to be behind the sudden increase.
According to preliminary data from Kei Sato at the University of Tokyo and colleagues, BA.4, BA.5 and BA.2.12.1 may have evolved to refavour infection of lung cells, rather than upper respiratory tract tissue – making them more similar to earlier variants, such as Alpha or Delta.