february 2021 • Pre Print
Effectiveness of first dose of COVID-19 vaccines against hospital admissions in Scotland: national prospective cohort study of 5.4 million people
Estudo de base populacional com 5.4 milhões de escoceses em que usam bases de dados interligadas para fazer corresponder dados de vacinação com dados hospitalares. A primeira dose da vacina BNT162b2 foi associada a uma redução de 85% (intervalo de confiança de 95% [IC] 76 a 91) para hospitalização relacionada a COVID-19 28-34 dias após a vacinação. No mesmo intervalo de tempo para a vacina ChAdOx1 o efeito foi de 94% (IC 95% 73 a 99). Os resultados do efeito da vacina combinada para a prevenção de hospitalização relacionada a COVID-19 foram comparáveis ao restringir a análise àqueles com idade ≥80 anos (81%; IC 95% 65 a 90 em 28-34 dias após a vacinação).
Adultos vacinados para covid-19
Coorte de base populacional
Decréscimo na taxa de hospitalização a 28-34 dias por covid-19 nas pessoas vacinadas para covid-19 com a vacina Pfizer-BioNTech de 85% (intervalo de confiança de 95% [IC] 76 a 91) e, no mesmo intervalo de tempo para a vacina ChAdOx1, de 94% (IC 95% 73 a 99).
Background: The BNT162b2 mRNA (Pfizer-BioNTech) and ChAdOx1 (Oxford- AstraZeneca) COVID-19 vaccines have demonstrated high efficacy against infection in phase 3 clinical trials and are now being used in national vaccination programmes in the UK and several other countries. There is an urgent need to study the ‘real-world’ effects of these vaccines. The aim of our study was to estimate the effectiveness of the first dose of these COVID-19 vaccines in preventing hospital admissions. Methods: We conducted a prospective cohort study using the Early Pandemic Evaluation and Enhanced Surveillance of COVID-19 (EAVE II) database comprising of linked vaccination, primary care, Real-Time Polymerase Chain Reaction (RT-PCR) testing, hospitalisation and mortality records for 5.4 million people in Scotland (covering ~99% of population). A time- dependent Cox model and Poisson regression models were fitted to estimate effectiveness against COVID-19 related hospitalisation (defined as 1- Adjusted Hazard Ratio) following the first dose of vaccine. Findings: The first dose of the BNT162b2 vaccine was associated with a vaccine effect of 85% (95% confidence interval [CI] 76 to 91) for COVID-19 related hospitalisation at 28-34 days post-vaccination. Vaccine effect at the same time interval for the ChAdOx1 vaccine was 94% (95% CI 73 to 99). Results of combined vaccine effect for prevention of COVID-19 related hospitalisation were comparable when restricting the analysis to those aged ≥80 years (81%; 95% CI 65 to 90 at 28-34 days post-vaccination). Interpretation: A single dose of the BNT162b2 mRNA and ChAdOx1 vaccines resulted in substantial reductions in the risk of COVID-19 related hospitalisation in Scotland. Funding: UK Research and Innovation (Medical Research Council); Research and Innovation Industrial Strategy Challenge Fund; Health Data Research UK.