Researchers analyzed healthcare data from 43,300 positive covid-19 cases in England between 29 March and 23 May this year. During the study period, 8600 patients were infected with the delta variant and 34,650 with the alpha variant. Although the proportion of cases caused by the delta variant was 20% overall, this number has increased to 74% of new cases in the week starting 31 May 2021.
The analysis found that 196 (2.3%) patients with the delta variant compared with 764 (2.2%) patients with the alpha variant were admitted to the hospital within 14 days, giving an adjusted hazard ratio of 2.26.
The risk of attending a hospital for emergency care or being admitted to hospital within 14 days of infection with the delta variant was also one and a half times greater compared with the alpha variant. Although a large proportion of patients were unvaccinated (74%) across both groups.
Dr. Gavin Dabrera, from PHE, said: "We already know that vaccination offers excellent protection against Delta and, as this variant accounts for over 99% of Covid cases in the UK, it is vital that those who have not received two doses of vaccine do so as soon as possible. It is still important that if you have Covid symptoms, stay home and get a PCR test as soon as possible."