Filenews 4 September 2021
More than twice the risk of being admitted to hospital, patients affected by the coronavirus Delta variant are at more than twice the risk of being admitted to hospital compared to those infected with the Alpha variant, according to a major British study.
The research, published in the Lancet Infectious Diseases, is the first to raise the risk of hospitalization from the Delta variant compared to Alpha, based on confirmed cases, after a complete sequence of the genome.
The researchers analyzed data from 43,338 positive cases of COVID-19 in England between March 29 and May 23, 2021. During the study period, 8,682 patients were infected with delta and 34,656 with alpha variant. Although the percentage of cases of delta variant was 20% overall, this increased to 74% of new cases - based on genome sequencing - in the week from May 31, 2021.
The analysis found that 196 patients (2.3%) with the Delta variant compared to 764 (2.2%) patients with the Alpha variant were admitted to hospital within 14 days, giving a risk probability of 2.26 (ranging from 1.32 to 3.89).
The risk of emergency care or hospitalization within 14 days of infection with the Delta variant was also one and a half times greater than the Alpha variant (risk of 1.45, with a range of 1.08 to 1.95). Most patients were not vaccinated (74%) in both groups.
Although the researchers did not have access to information on comorbidities in patients contributing to the risk of hospitalization, which is a limitation for the study, the scientists indirectly took this possibility into account, using data such as age, gender, ethnicity and withdrawal levels. Other limitations to the study's conclusions are that some demographics may increase the chances of hospitalization, as does the selection of genome sequencing samples.
The study was carried out by researchers from Public Health England and the University of Cambridge and was funded by UK Research and Innovation, the Medical Research Council, the UK Department of Health and Social Care and the National Institute for Health Research.
Anne Presanis, one of the study's main authors and a senior statistician at the Biostatistics Unit at the University of Cambridge, said: "Our analysis highlights that in the absence of vaccination, any delta epidemics will impose more weight on the health system than the Alpha epidemic."
The British Medical Journal notes that a preliminary study from Scotland had already reported earlier, doubling the risk of hospitalization with the Delta variant compared to the Alpha variant. The Scottish study had used the patients' initial molecular testing (PCR) test results and determined what variant they had by testing a particular gene that is most common in delta variant.
