A new study adds to growing evidence suggesting that the Delta coronavirus variant is not only highly transmissible but also more dangerous.

Covid-19 patients infected with the Delta variant had about double the risk of hospitalization compared to those infected with the Alpha variant, according to the study published Friday in the journal Lancet Infectious Diseases.
"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.

"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.
'Getting fully vaccinated is crucial'

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 of 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.

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.

"Our analysis highlights that in the absence of vaccination, any Delta outbreaks will impose a greater burden on healthcare than an Alpha epidemic," Dr Anne Presanis, one of the study's lead authors and senior statistician at the University of Cambridge, said in a news release Friday.

"Getting fully vaccinated is crucial for reducing an individual's risk of symptomatic infection with Delta in the first place, and, importantly, of reducing a Delta patient's risk of severe illness and hospital admission," Presanis said.