People infected with the SARS CoV-2 Delta variant have double the risk of hospitalization compared with those infected with the Alpha variant, finds a new study.
The Lancet Infectious Diseases journal, analysing more than 40,000 Covid-19 cases in the UK confirmed by virus genome sequencing finds a two-fold increased risk of hospitalisation from Delta versus Alpha variant infections.
Researcher Gavin Dabrera, Consultant Epidemiologist at the National Infection Service, Public Health England said, “This study confirms previous findings that people infected with Delta are significantly more likely to require hospitalisation than those with Alpha, although most cases included in the analysis were unvaccinated” .
Dabrera added , “We already know that vaccination offers excellent protection against Delta and as this variant accounts for over 98 percent of Covid-19 cases in the UK, it is vital that those who have not received two doses of vaccine do so as soon as possible,”.
The Delta variant was first reported in India in December 2020 and early studies found it to be up to 50 percent more transmissible than the variant of Covid-19 that had previously gained dominance worldwide, known as the alpha variant, first identified in Kent, the UK.
The team analysed healthcare data from 43,338 positive Covid-19 cases in England between March 29 and May 23, 2021, including information on vaccination status, emergency care attendance, hospital admission, and other demographic characteristics.
In all cases included in the study, samples of the virus taken from patients underwent whole-genome sequencing to confirm which variant had caused the infection. There were 34,656 cases of the Alpha variant and 8,682 cases of the Delta variant, the study indicated.
The proportion of Delta cases in the study period overall was 20 percent, it grew to account for around two-thirds of new Covid-19 cases in the week starting May 17, 2021 , indicating it had overtaken alpha to become the dominant variant in England.
Factors that are known to affect susceptibility to severe illness from Covid-19, including age, ethnicity and vaccination status. Indicating the importance of vaccination, the team also emphasised that multiple studies have shown that full vaccination prevents both symptomatic infection and hospitalisation, for both Alpha and Delta variant.