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).
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Real world data from PHE, published as a pre-print, demonstrated two doses of COVID-19 Vaccine AstraZeneca are 92% effective against hospitalisation 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 hospitalisations 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 hospitalisation is supported by recent data showing strong T-cell response to COVID-19 Vaccine AstraZeneca, which should correlate with high and durable protection.
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.â€
The analysis included 14,019 cases of the Delta variant – 166 of whom were hospitalised – 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.
AstraZeneca announced results from the STORM CHASER trial assessing the safety and efficacy of AZD7442, a long-acting antibody (LAAB) combination, for the prevention of symptomatic COVID-19 in participants recently exposed to the SARS-CoV-2 virus. The trial did not meet the primary endpoint of post-exposure prevention of symptomatic COVID-19 with AZD7442 compared to placebo.
Trial participants were unvaccinated adults 18 years and over with confirmed exposure to a person with a case of the SARS-CoV-2 virus within the past eight days. In the overall trial population, AZD7442 reduced the risk of developing symptomatic COVID-19 by 33% (95% confidence interval (CI): -26, 65) compared to placebo, which was not statistically significant (Table 1).
The trial included 1,121 participants in a 2:1 randomisation AZD7442 to placebo, with 23 cases of symptomatic COVID-19 accrued in the AZD7442 arm (23/749) and 17 cases accrued in the placebo arm (17/372). All participants had a negative SARS-CoV-2 antibody test on the day of dosing to exclude prior infection, and a nasopharyngeal swab was also collected and subsequently analysed for SARS-CoV-2 by RT-PCR to detect virus.
Given the importance of finding therapies for COVID-19 and to help interpret trial results during the pandemic, additional analyses were performed and are being communicated .
In a pre-planned analysis of SARS-CoV-2 PCR positive (detectable virus) and PCR negative (no detectable virus) participants, AZD7442 reduced the risk of developing symptomatic COVID-19 by 73% (95% CI: 27, 90) compared with placebo, in participants who were PCR negative at time of dosing. In a post-hoc analysis, in participants who were PCR negative at baseline, AZD7442 reduced the risk of developing symptomatic COVID-19 by 92% (95% CI: 32, 99) versus placebo more than seven days following dosing, and by 51% (95% CI: -71, 86) up to seven days following dosing. ■