Covid-19 patients infected with the Delta variant face about double the risk of hospitalization compared to those infected with the Alpha variant, according to a new study out of the United Kingdom.
"The results suggest that patients with the Delta variant had more than two times the risk of hospital admission compared with patients with the Alpha variant," researchers from Public Health England and the University of Cambridge wrote in their new study, published Friday in the journal Lancet Infectious Diseases.
"Emergency care attendance combined with hospital admission was also higher for patients with the Delta variant, showing increased use of emergency care services as well as inpatient hospitalization," the researchers wrote.
The study included data on 8,682 Covid-19 patients in England who were infected with the Delta variant and 34,656 infected with the Alpha variant. Across both groups, most of the patients — 74% — were unvaccinated.
The patients were tested for Covid-19 between March 29 and May 23 this year, and the researchers examined how many of them were hospitalized.
In general, 2.3% of patients with Delta and 2.2% of patients with Alpha were admitted to the hospital within two weeks after they were tested for Covid-19. But once the researchers accounted for certain factors that could raise a patient's risk for hospitalization, such as age or vaccination status, they found Delta was associated with a 2.26-fold increased risk of hospitalization compared with Alpha and 1.45-fold increased risk of requiring emergency care or hospital admission.
Some context: The researchers noted that their study results are similar to separate research previously conducted in Scotland that also found a higher risk of hospital admission within 14 days for patients infected with Delta versus Alpha.
The researchers also noted that new Covid-19 infections in England have been increasingly caused by the Delta variant. Although the proportion of cases in the study caused by the Delta variant was 20% overall, the researchers wrote, "this increased to 74% of new sequenced cases in the week starting May 31, 2021."
During this summer in the United States, the Delta variant overtook the Alpha variant, first identified in the United Kingdom, as the dominant coronavirus strain circulating.