Single shot of Pfizer, AstraZeneca ‘barely’ work against Delta variant, reveals new study
The researchers found that the Delta variant, first detected in India, has mutations that allow it to evade some of the neutralising antibodies produced either by vaccines or previous infection.
A single shot of Pfizer-BioNTech or AstraZeneca vaccines “barely” induce neutralising antibodies against the Delta variant in individuals previously not infected with Sars-Cov-2, according to new research. The study, published in the journal Nature, highlighted the threat posed by viral mutations of coronavirus disease (Covid-19) as the Delta variant is rapidly becoming the dominant strain across the world.
The researchers found that the Delta variant, first detected in India, has mutations that allow it to evade some of the neutralising antibodies produced either by vaccines or previous coronavirus infection. The study, however, suggests that fully vaccinated individuals, with two doses of Pfizer-BioNtech or AstraZeneca vaccine, retain significant protection against the highly contagious Delta variant.
The latest findings underline the urgency for administering the recommended regimen of two shots of Pfizer-BioNTech or AstraZeneca vaccine to contain the virus at a time when Delta variant, a subtype of B.1.617 lineage, is threatening the pandemic response worldwide. India’s second wave of Covid-19 is believed to be largely driven by the Delta strain of coronavirus, which has been classified as a ‘variant of concern’ by the World Health Organization (WHO).
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In India, less than 5% of the population has been fully vaccinated and, taking the findings of the study at face value, the prevalence of Delta variant in the country suggests a large section remains under threat of the deadly contagion. While India has ramped up the vaccination drive in the past few days, experts have said that the third wave of Covid-19 could peak in October, given the low overall vaccination coverage.
After weeks of lockdown-like restrictions in several states, authorities have started to gradually drop stringent measures amid a decline in Covid-19 cases. But the World Health Organization (WHO) emergencies programme head Michael Ryan on Wednesday urged countries to take extreme caution when reopening economies.
“Countries opening up who have very low levels of vaccination coverage in the presence of variants is a real toxic mixture for your hospitals filling up again. And this is something that must absolutely be avoided,” said Ryan during a news conference in Geneva.
