“Patients with the delta variant had more than two times the risk of hospital admission.” That’s according to a UK study published in The Lancet comparing the delta variant “to the previously dominant alpha variant (B.1.1.7).”
Recall that the alpha variant, or “UK variant,” was a particularly infectious “variant of concern” when it first appeared in November 2020. The delta variant started in India in December 2020, was first detected in England in March 2021, and replaced alpha due to its higher transmissibility.
Is the Delta Variant more dangerous?
The study in The Lancet included all patients infected with the delta or the alpha variant between late March and late May 2021 whose infection was identified with whole-genome sequencing. This amounted to over 43,000 cases.
According to the research team, “it is the largest study to date to report on hospitalisation risk for the delta variant compared with the alpha variant.” Researchers had full access to Public Health England’s Second Generation Surveillance System and its COVID-19-associated deaths dataset.
The study compared the risk of hospitalisation for patients with each variant. According to the authors, “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.
“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 hospitalisation”.
While the study took into account patients’ vaccination status, the small number of vaccinated people who fell seriously ill made a comparison between alpha and delta in vaccinated individuals impossible. During the study period, the proportion of the UK population fully vaccinated increased from 5% to 35%.
Other UK studies have shown that vaccines remain effective against the delta variant. One found 88% protection against delta variant with Pfizer immunisation and 67% when vaccinated with AstraZeneca.
A final fact: in contrast to the common misconception that Covid-19 is a disease of older people, the median age of Covid-positive people in the UK during the study period was 31 years of age.
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