Coronavirus (COVID-19) vaccine certification: evidence paper update

Annex B: Vaccine effectiveness

Vaccine effectiveness against Delta in UK

• Vaccine Effectiveness Expert Panel (VEEP), published on 29 October 2021 the consensus view of vaccine effectiveness for different vaccines and doses and outcomes, which was reached on 24 September 2021^[202]. The values presented in the table below are the consensus judgement of the Vaccine Effectiveness Expert Panel for Delta, they also published a table for Alpha (not shown here). The panel considers a wide range of domestic and international data, and draws a conclusion as to the most accurate values, given the data. Green shows high confidence (Evidence from studies is consistent and comprehensive), Orange shows medium confidence (Evidence is emerging but may be inconsistent requires further analysis) and Red shows low confidence (Little evidence is available at present and results are inconclusive).

• REal-time Assessment of Community Transmission (REACT-1) - the UK study analysed swabs taken by nearly 100,000 people in England between 24 June 2021 and 12 July 2021, 100% of which were Delta variant. Based on the findings the researchers estimated that "fully vaccinated people in this testing round had between 50% - 60% reduced risk of infection, including asymptomatic infection, compared to unvaccinated people. In addition, double vaccinated people were less likely than unvaccinated people to test positive after coming into contact with someone who had COVID-19 (3.84% vs 7.23%)" ^{[203] [204]}.
• Office for National Statistics COVID-19 Infection Survey is a large survey of randomly selected private households across the UK, where RT-PCR tests were performed following a schedule, irrespective of symptoms, vaccination and prior infection. ONS data from during the Delta period shows that two vaccine doses (14 days or more previously) reduced the risk of testing positive by 67% (95% confidence interval: 64% to 70%) compared to those not yet vaccinated (or 21 days or more before vaccination) without evidence of prior infection^[205].
• The EAVE II study undertook cohort analysis of the population in Scotland and reported that from 1 April to 27 September 2021, there were 201 COVID-19 deaths in the group studied. In the 16-39 age bracket, 17 unvaccinated people died and no fully vaccinated people died. The Pfizer-BioNTech vaccine was 95% effective in 40-59 year olds and 87% effective in people 60+. The Oxford-AstraZeneca vaccine was 88% effective in 40-59 year olds and 90% effective in people aged 60+. In people of all ages who had been double-vaccinated at least two weeks before a positive PCR test, the vaccines offer around 90% against COVID-19 deaths caused by the Delta variant^[206].