COVID-19 Vaccine AstraZeneca effective against Delta (‘Indian’) variant

New data from Public Health England (PHE) demonstrated COVID-19 Vaccine AstraZeneca offers high levels of protection against the Delta variant (B.1.617.2; formerly the ‘Indian’ variant).

Real world data from PHE, published as a pre-print, demonstrated two doses of COVID-19 Vaccine AstraZeneca are 92% effective against hospitalization due to the Delta variant and showed no deaths among those vaccinated. The vaccine also showed a high level of effectiveness against the Alpha variant (B.1.1.7; formerly the ‘Kent’ variant) with an 86% reduction of hospitalizations and no deaths reported.

The data suggest that vaccine effectiveness against milder symptomatic disease, although significant, was lower. Vaccine effectiveness against symptomatic disease was 74% against the Alpha variant and 64% against the Delta variant.

The higher efficacy against severe disease and hospitalization is supported by recent data showing strong T-cell response to COVID-19 Vaccine AstraZeneca, which should correlate with high and durable protection.¹

Mene Pangalos, Executive Vice President, BioPharmaceuticals R&D, said: “This real world evidence shows that COVID-19 Vaccine AstraZeneca provides a high level of protection against the Delta variant, which is currently a critical area of concern given its rapid transmission. The data show that the vaccine will continue to have a significant impact around the world given that it continues to account for the overwhelming majority of supplies to India and the COVAX facility.”

The analysis included 14,019 cases of the Delta variant – 166 of whom were hospitalized – between 12 April and 4 June, looking at emergency hospital admissions in England.
This real world evidence against the Delta variant is based on limited follow up after the second dose which could impact the effectiveness estimate.

The Delta variant is a key contributor to the current wave of infection in the Indian subcontinent and beyond. It has recently replaced the Alpha variant as the dominant strain in Scotland and is responsible for a notable increase in cases in the United Kingdom. The WHO Strategic Advisory Group of Experts on Immunization (SAGE) has recommended COVID-19 Vaccine AstraZeneca in countries where new variants, like the Delta variant of concern, are prevalent.

COVID-19 Vaccine AstraZeneca, formerly AZD1222

COVID-19 Vaccine AstraZeneca was co-invented by the University of Oxford and its spin-out company, Vaccitech. It uses a replication-deficient chimpanzee viral vector based on a weakened version of a common cold virus (adenovirus) that causes infections in chimpanzees and contains the genetic material of the SARS-CoV-2 virus spike protein. After vaccination, the surface spike protein is produced, priming the immune system to attack the SARS-CoV-2 virus if it later infects the body.

The vaccine has been granted a conditional marketing authorization or emergency use in more than 80 countries across six continents. More than 500 million doses of COVID-19 Vaccine AstraZeneca have been supplied to 165 countries worldwide, including more than 100 countries through the COVAX Facility.

References

[1] Parry HM, et al. (2021) Single Vaccination with BNT162b2 or ChAdOx1 in Older People Induces Equivalent Antibody Generation but Enhanced Cellular Responses after ChAdOx1. Preprints with The Lancet

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