Covid-19 patients infected with the Delta variant had about twice the risk of hospitalization compared to those infected with the Alpha variant, according to the study published in the journal Lancet Infectious Diseases on Friday .
“The results suggest that patients with the Delta variant were more than twice as likely to be hospitalized as patients with the Alpha variant,” write researchers from Public Health England and the University of Cambridge in their new study.
“The participation in emergencies in combination with hospitalization was also higher in patients with the Delta variant, which shows an increased use of emergency services and inpatient hospital stays,” the researchers write.
The study included data from 8,682 Covid-19 patients in England who were infected with the Delta variant and 34,656 with the Alpha variant. In 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 looked at how many of them were hospitalized.
In general, 2.3% of patients with Delta and 2.2% of patients with Alpha were hospitalized within two weeks of being tested for Covid-19. But once the researchers considered certain factors that could increase a patient’s risk of hospitalization, such as age or vaccination status, they found that Delta compared to Alpha had a 2.26-fold increased risk of hospitalization and a 1, A 45-fold increased risk of emergency was associated with nursing or hospitalization.
The researchers found that their study results are comparable to separate studies previously conducted in Scotland which also found a higher risk of hospitalization within 14 days for Delta compared to Alpha infected patients.
“Our analysis shows that without vaccination, delta outbreaks are more of a burden to health care than an alpha epidemic,” said Dr. Anne Presanis, one of the study’s lead authors and chief statistician at the University of Cambridge, in a press release Friday.
“Full vaccination is critical to reducing the risk of symptomatic Delta infection and, most importantly, reducing the risk of serious illness and hospitalization of a Delta patient,” said Presanis.
“This is no surprise”
Some doctors and scientists who weren’t involved in the new study said the results confirm what has already been believed – that the Delta variant is more likely to cause serious illness.
“This data confirms what we are seeing in clinical practice, namely that the Delta variant is not only more contagious than the original or the Alpha variants, but also causes more severe illness in populations who previously had only mild infections,” said Dr . David Strain, senior clinical lecturer at the University of Exeter who was not involved in the study, in a written statement distributed by the UK Science Media Center.
“It underscores the need for a comprehensive vaccination program in younger adults and clearly shows that the prejudices that they will not get a severe Covid virus are no longer true,” said Strain. “This is no surprise because the two factors that make the delta variant more contagious will also play a role in the severity of the disease.”
The researchers also found in their study that new Covid-19 infections in England were increasingly caused by the Delta variant. Although the proportion of cases in the study caused by the Delta variant totaled 20%, the researchers wrote, “This increased to 74% of the newly sequenced cases in the week beginning May 31, 2021.”
During that summer, the Delta variant in the United States overtook the Alpha variant, which was first identified as the dominant circulating strain of coronavirus in the UK.
“The Delta variant was responsible for the spike in Covid cases in the UK this summer, and many of us have even heard of vaccinated people who became infected,” said Dr. Zania Stamataki, a virus immunologist at the University of Birmingham who was not involved in infecting the new study, said in a separate statement from the Science Media Center.
“The new study” measures hospital admissions as a surrogate marker for severe illness, and the results are clear: The Delta variant increases hospital admissions compared to the Alpha variant previously used in the UK, “said Stamataki. “Along with previous studies showing that Delta is 50% more contagious than Alpha, there is increasing evidence that we are dealing with a very dangerous variant. Both vaccine doses are needed for maximum protection. “