Abstract
SummaryBackgroundThe BNT162b2 mRNA (Pfizer–BioNTech) and ChAdOx1 nCoV-19 (Oxford–AstraZeneca) COVID-19 vaccines have shown high efficacy against disease in phase 3 clinical trials and are now being used in national vaccination programmes in the UK and several other countries. Studying the real-world effects of these vaccines is an urgent requirement. The aim of our study was to investigate the association between the mass roll-out of the first doses of these COVID-19 vaccines and hospital admissions for COVID-19.MethodsWe did a prospective cohort study using the Early Pandemic Evaluation and Enhanced Surveillance of COVID-19—EAVE II—database comprising linked vaccination, primary care, real-time reverse transcription-PCR testing, and hospital admission patient records for 5·4 million people in Scotland (about 99% of the population) registered at 940 general practices. Individuals who had previously tested positive were excluded from the analysis. A time-dependent Cox model and Poisson regression models with inverse propensity weights were fitted to estimate effectiveness against COVID-19 hospital admission (defined as 1–adjusted rate ratio) following the first dose of vaccine.FindingsBetween Dec 8, 2020, and Feb 22, 2021, a total of 1 331 993 people were vaccinated over the study period. The mean age of those vaccinated was 65·0 years (SD 16·2). The first dose of the BNT162b2 mRNA vaccine was associated with a vaccine effect of 91% (95% CI 85–94) for reduced COVID-19 hospital admission at 28–34 days post-vaccination. Vaccine effect at the same time interval for the ChAdOx1 vaccine was 88% (95% CI 75–94). Results of combined vaccine effects against hospital admission due to COVID-19 were similar when restricting the analysis to those aged 80 years and older (83%, 95% CI 72–89 at 28–34 days post-vaccination).InterpretationMass roll-out of the first doses of the BNT162b2 mRNA and ChAdOx1 vaccines was associated with substantial reductions in the risk of hospital admission due to COVID-19 in Scotland. There remains the possibility that some of the observed effects might have been due to residual confounding.FundingUK Research and Innovation (Medical Research Council), Research and Innovation Industrial Strategy Challenge Fund, Health Data Research UK.
Highlights
In December, 2019, there was an outbreak of the novel SARS-CoV-2 in Wuhan, China, which was later declared as the COVID-19 pandemic by WHO
We found that a single dose of the BNT162b2 mRNA COVID-19 vaccine was associated with a vaccine effect of 91% for hospital admissions due to COVID-19 28–34 days after vaccination
Rapid uptake of the BNT162b2 mRNA and ChAdOx1 vaccines was observed over the study period, with 65–79 years the age group with the highest uptake (85·9%; 651 942 of 758 946)
Summary
In December, 2019, there was an outbreak of the novel SARS-CoV-2 in Wuhan, China, which was later declared as the COVID-19 pandemic by WHO. Since the beginning of the pandemic and as of April 20, 2021, more than 141 million cases and 3 millions deaths have been reported in more than 223 countries and territories worldwide. Authorisation of the first COVID-19 vaccines occurred soon after publication of the initial phase 3 safety and efficacy studies,[2] and the UK was one of the first countries to license these vaccines for use.[1] As of April 13, 2021, first-dose vaccine coverage of about 50% has been reported in Scotland with more than 2·6 million vaccines administered across the Scottish population, and delivery targeted at specified priority groups of those most at risk of harm (including those aged 50 years and older and health-care workers; appendix p 1).[1,3]
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