COVID Delta variant doubles the risk of hospitalisation, finds UK study

The Delta variant of coronavirus doubles the risk of hospitalisation from the disease, as compared with the people infected with the Alpha variant of COVID-19, a UK study, published in the Lancet, said. 

The study analysed over 40,000 cases of COVID-19 in the UK. By virus genome sequencing, the study found a two-fold increased risk of hospitalisation from the Delta variant.

"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," said Gavin Dabrera, Consultant Epidemiologist at the National Infection Service of the Public Health England.

He 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 of coronavirus was first detected in India in October last year and is found to be 50 percent more transmissible than the alpha variant, which was first detected in the UK and gained dominance worldwide. 

Researchers analysed data from 43,338 COVID-19 cases from March 29, 2021 to May 23, 2021. The data included information on vaccination status, emergency care attendance, hospital admission, and other demographic characteristics.

The samples of coronavirus taken from the patients underwent whole-genome sequencing to confirm which variant of COVID-19 caused the infection. The study revealed that the Alpha variant had caused 80 percent of infection, 34,656 infections while the Delta variant caused 80 percent, 8,682 cases. 

The study further revealed that the Delta cases grew to account for nearly two-thirds of new COVID-19 cases in the week starting from May 17 (65 percent, 3,973/6,090), and it overtook the Alpha variant, becoming the dominant strain in the UK.

It said that nearly one in 50 patients were hospitalised within 14 days of their infection, with 2.2 percent Alpha cases, 764 out of 34,656 and 2.3 percent Delta cases, 196 out of 8,682 cases. 

Taking in account the factors, such as age, ethnicity and vaccination status, known to affect susceptibility to severe illness from COVID-19, the researchers found that the hospitalisation risk from the Delta variant infection was doubled compared with the alpha variant (2.26-fold increase in risk).

The team also emphasised the importance of vaccination, saying that multiple studies have shown that full vaccination prevents both symptomatic infection and hospitalisation, for both Alpha and Delta variants of coronavirus.