Takeaway
- The mass roll-out of the first doses of the BNT162b2 mRNA (Pfizer-BioNTech) and ChAdOx1 (Oxford-AstraZeneca) vaccines in Scotland was associated with a reduced risk of COVID19-related hospital admissions at 28-34 days.
- Such large post-licensure epidemiological studies may help assess the effectiveness of vaccines at a population level in a real-world setting, thereby confirming and/or complementing the findings of pre-licensure clinical trials.
Study details
- This prospective, nationwide study analysed data from the Early Pandemic Evaluation and Enhanced Surveillance of COVID19-EAVE II-database.
- Data were available for 5.4 million people registered at 940 general practices across Scotland
- Primary outcome was vaccine effect assessed as COVID19-related hospital admissions or hospital admissions within 28 days of a positive reverse transcription-polymerase chain reaction test for COVID19.
- Funding: UK Research and Innovation (Medical Research Council), Research and Innovation Industrial Strategy Challenge Fund, Health Data Research UK and others.
- Between 8 December 2020 and 15 February 2021, 30% (1,331,993) of 4,409,588 adults were vaccinated.
- Vaccine effect for the first dose of the BNT162b2 mRNA vaccine was 91% (95% CI, 85-94%) and for ChAdOx1 was 88% (95% CI, 75-94%) against COVID19 hospitalisation at 28-34 days.
- At 28-34 days, combined vaccine effect against COVID19 hospitalisation across different age groups was:
- age, 18-64 years: 92% (95% CI, 82-97%);
- age, 65-79 years: 93% (95% CI, 73-98%); and
- age, ≥80 years: 83% (95% CI, 72-89%).
- For people aged ≥80 years, vaccine effect at 28-34 days was 88% and 81% for the BNT162b2 mRNA and ChAdOx1 vaccines, respectively.
- Short follow-up period.
- Residual confounding may be present.
References
References