Story at a glance
- The Delta variant of COVID-19 has been linked to an increased risk of hospitalizations.
- Vaccine efficacy was shown to have a positive but diminished effect on the Delta variant, dubbed B.1.617.2.
- CDC data suggests the Delta variant composes at most 3.4 percent of cases in the U.S.
The Delta variant of COVID-19, already on public health watchlists as a more transmissible form of the coronavirus, is linked to an increased likelihood of hospitalizations, according to a Scottish study.
Published in The Lancet on Monday, researchers cross-referenced hospitalization rates with the COVID-19 variant that infected patients.
Using the S gene as an identifier for which variant was present in each patient that tested positive, scientists were able to distinguish the Delta variant from the Alpha variant, which was previously the most prevalent COVID variant in circulation in Scotland.
About 99 percent of Delta variant samples were S gene positive, while Alpha samples were S gene negative.
Sourcing hospitalization data from Scotland’s EAVE II data surveillance bank, scientists looked at the risk of hospital admission among patients whose tests included the S gene, signifying a Delta variant infection.
According to the analysis, 377 people were hospitalized due to a COVID-19 infection between April 1 to June 6, 2021. About one-third, or 134, of these hospitalizations were due to a Delta variant infection.
“Risk of COVID-19 hospital admission was approximately doubled in those with the Delta VOC when compared to the Alpha VOC, with risk of admission particularly increased in those with five or more relevant comorbidities,” the report explained.
The authors also noted that both the AstraZeneca and Pfizer vaccines were effective in treating those with a COVID-19 infection, regardless of the variant. However, people infected with the Delta variant experienced “diminished” benefits from the vaccines in comparison to the Alpha variant.
Pfizer’s vaccine provided a 79 percent protection against the Delta variant, while it offered a 92 percent efficacy against the Alpha variant. AstraZeneca’s numbers were similar, giving about 73 percent protection to S gene-negative patients versus a 60 percent efficacy to those who were S-gene positive.
“Both the Oxford–AstraZeneca and Pfizer–BioNTech COVID-19 vaccines were effective in reducing the risk of SARS-CoV-2 infection and COVID-19 hospitalisation in people with the Delta VOC, but these effects on infection appeared to be diminished when compared to those with the Alpha VOC,” the authors concluded.
Current CDC estimates suggest that the Delta variant is responsible for up to 3.4 percent of infections in the U.S. Denoted as B.1.617.2, it is labeled as a “variant of interest” and not yet a “variant of concern.”