COVID case rates hit new high for England, study finds

Coronavirus infections in England climbed to a new record high with one in 16 or 6.37 per cent testing positive for COVID-19 last month -- more than double the one in 35 reported in February, according to a new study.

Experts behind the long-running Real-time Assessment of Community Transmission (REACT-1) analysis in the UK by Imperial College London found that infections were doubling every 30 days with an estimated reproduction number, or the rate at which infections multiply, above the cut-off mark of one at 1.07.

According to the surveillance data of the study, released on Wednesday, based on almost 110,000 swab tests taken between March 8 and 31, the vast majority of the analysed positive samples were the Omicron BA.2 stealth variant , named due to the absence of certain genetic changes that can distinguish this variant easily from others.

These trends are concerning since when a very high number of people are infected, this may lead to more people becoming seriously ill and needing to go to hospital, said Professor Paul Elliott, director of the REACT programme from Imperial's School of Public Health.

Although restrictions have ended, I would urge people to still behave cautiously to help protect others who might be vulnerable, and avoid contact with other people if you have symptoms. This will help to slow the spread of the virus and lessen its impact on the NHS and our lives more broadly as we enter this next phase of the epidemic, he said.

A very small number of recombinant Omicron variants - XE and XL - were also detected during the surveillance, which are hybrids of the original BA.1 Omicron strain and the BA.2 mutation. It had emerged earlier that UK health experts are currently monitoring and studying the XE strain.

The REACT research noted because the number of these recombinants was so small, it's not possible to tell from the data whether these variants are more transmissible than others.

Compared to previous data, infections have risen in all age groups and remain highest in primary school-aged children, with almost one in 10 five to 11 year olds testing positive.

However, the most recent trends show that the rate of new infections is likely slowing or falling in the younger age groups aged five to 54. This was not seen in older people above the age of 55 where infections were found to still be rising, having almost tripled to 4.61 per cent in the oldest age group aged 75 and above.

The researchers pointed out that booster vaccines were rolled out by the UK's National Health Service (NHS) in September last year, starting with older age groups. Younger people therefore received their third dose more recently than older people, which may partly explain the differences.