Scientists are studying how well Covid-19 vaccines work against the delta variant of SARS-CoV-2. We discuss the latest findings.
The delta variant of SARS-CoV-2, which was first identified in India, is now the dominant form of the virus in the United Kingdom. In the United States, at least 10% of new cases are with this variant.
Data from the U.K. show that new SARS-CoV-2 infections have increased by 31% in the past 7 days.
Moreover, an analysis from Public Health England (PHE) suggests that the delta variant is more transmissible than previous ones and that it is more likely to lead to treatment in the hospital.
Yet recent data indicate that vaccines are effective at preventing severe Covid-19 caused by the delta variant that would require hospital treatment.
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In this article, we present up-to-date research on how well Covid-19 vaccines work against the delta variant.
A recent analysis from PHE looks at how likely people who had an infection with the delta variant were to need treatment in the hospital.
The report puts the protection from requiring hospital treatment for Covid-19 at 71% after one dose and at 92% after two doses of the Oxford-AstraZeneca vaccine.
The Pfizer vaccine was 94% effective at preventing hospitalization after the first dose and 96% after two doses.
In India, the Oxford-AstraZeneca Covid-19 vaccine bears the name Covishield.
The report, which has not been peer-reviewed yet, puts these percentages on a par with protection against the alpha variant, or B.1.1.7, which scientists first identified in the U.K.
“These findings indicate very high levels of protection against hospitalization with the delta variant with one or two doses of either vaccine,” the authors write.
It comes after an earlier report that indicates Covid-19 vaccines were less effective at protecting people from Covid-19 if they had only received the first dose of the Pfizer-BioNTech or Oxford-AstraZeneca vaccines.
However, in the analysis, which has not yet undergone peer review, the researchers measured any symptomatic case of Covid-19, regardless of severity.
