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Effectiveness of the Pfizer-BioNTech and Oxford-AstraZeneca vaccines on covid-19 related symptoms, hospital admissions, and mortality in older adults in England: test negative case-control study.
BMJ. 2021 05 13; 373:n1088.BMJ

Abstract

OBJECTIVE

To estimate the real world effectiveness of the Pfizer-BioNTech BNT162b2 and Oxford-AstraZeneca ChAdOx1-S vaccines against confirmed covid-19 symptoms (including the UK variant of concern B.1.1.7), admissions to hospital, and deaths.

DESIGN

Test negative case-control study.

SETTING

Community testing for covid-19 in England.

PARTICIPANTS

156 930 adults aged 70 years and older who reported symptoms of covid-19 between 8 December 2020 and 19 February 2021 and were successfully linked to vaccination data in the National Immunisation Management System.

INTERVENTIONS

Vaccination with BNT162b2 or ChAdOx1-S.

MAIN OUTCOME MEASURES

Primary outcomes were polymerase chain reaction confirmed symptomatic SARS-CoV-2 infections, admissions to hospital for covid-19, and deaths with covid-19.

RESULTS

Participants aged 80 years and older vaccinated with BNT162b2 before 4 January 2021 had a higher odds of testing positive for covid-19 in the first nine days after vaccination (odds ratio up to 1.48, 95% confidence interval 1.23 to 1.77), indicating that those initially targeted had a higher underlying risk of infection. Vaccine effectiveness was therefore compared with the baseline post-vaccination period. Vaccine effects were noted 10 to 13 days after vaccination, reaching a vaccine effectiveness of 70% (95% confidence interval 59% to 78%), then plateauing. From 14 days after the second dose a vaccination effectiveness of 89% (85% to 93%) was found compared with the increased baseline risk. Participants aged 70 years and older vaccinated from 4 January (when ChAdOx1-S delivery commenced) had a similar underlying risk of covid-19 to unvaccinated individuals. With BNT162b2, vaccine effectiveness reached 61% (51% to 69%) from 28 to 34 days after vaccination, then plateaued. With ChAdOx1-S, effects were seen from 14 to 20 days after vaccination, reaching an effectiveness of 60% (41% to 73%) from 28 to 34 days, increasing to 73% (27% to 90%) from day 35 onwards. On top of the protection against symptomatic disease, a further 43% (33% to 52%) reduced risk of emergency hospital admission and 51% (37% to 62%) reduced risk of death was observed in those who had received one dose of BNT162b2. Participants who had received one dose of ChAdOx1-S had a further 37% (3% to 59%) reduced risk of emergency hospital admission. Follow-up was insufficient to assess the effect of ChAdOx1-S on mortality. Combined with the effect against symptomatic disease, a single dose of either vaccine was about 80% effective at preventing admission to hospital with covid-19 and a single dose of BNT162b2 was 85% effective at preventing death with covid-19.

CONCLUSION

Vaccination with either one dose of BNT162b2 or ChAdOx1-S was associated with a significant reduction in symptomatic covid-19 in older adults, and with further protection against severe disease. Both vaccines showed similar effects. Protection was maintained for the duration of follow-up (>6 weeks). A second dose of BNT162b2 was associated with further protection against symptomatic disease. A clear effect of the vaccines against the B.1.1.7 variant was found.

Authors+Show Affiliations

Public Health England, London, UK jamie.lopezbernal2@phe.gov.uk. NIHR Health Protection Research Unit in Vaccines and Immunisation, London School of Hygiene and Tropical Medicine, London, UK. NIHR Health Protection Research Unit in Respiratory Infections, Imperial College London, London, UK.Public Health England, London, UK. NIHR Health Protection Research Unit in Vaccines and Immunisation, London School of Hygiene and Tropical Medicine, London, UK.Public Health England, London, UK.University of Strathclyde, Glasgow, UK.Public Health England, London, UK.Public Health England, London, UK.Public Health England, London, UK.Public Health Wales, Cardiff, UK.Public Health Wales, Cardiff, UK.Public Health Agency Northern Ireland, Belfast, UK.Public Health England, London, UK.Health Protection Scotland, Glasgow, UK.Health Protection Scotland, Glasgow, UK.Health Protection Scotland, Glasgow, UK.Public Health England, London, UK. NIHR Health Protection Research Unit in Vaccines and Immunisation, London School of Hygiene and Tropical Medicine, London, UK.

Pub Type(s)

Journal Article
Observational Study

Language

eng

PubMed ID

33985964

Citation

Lopez Bernal, Jamie, et al. "Effectiveness of the Pfizer-BioNTech and Oxford-AstraZeneca Vaccines On Covid-19 Related Symptoms, Hospital Admissions, and Mortality in Older Adults in England: Test Negative Case-control Study." BMJ (Clinical Research Ed.), vol. 373, 2021, pp. n1088.
Lopez Bernal J, Andrews N, Gower C, et al. Effectiveness of the Pfizer-BioNTech and Oxford-AstraZeneca vaccines on covid-19 related symptoms, hospital admissions, and mortality in older adults in England: test negative case-control study. BMJ. 2021;373:n1088.
Lopez Bernal, J., Andrews, N., Gower, C., Robertson, C., Stowe, J., Tessier, E., Simmons, R., Cottrell, S., Roberts, R., O'Doherty, M., Brown, K., Cameron, C., Stockton, D., McMenamin, J., & Ramsay, M. (2021). Effectiveness of the Pfizer-BioNTech and Oxford-AstraZeneca vaccines on covid-19 related symptoms, hospital admissions, and mortality in older adults in England: test negative case-control study. BMJ (Clinical Research Ed.), 373, n1088. https://doi.org/10.1136/bmj.n1088
Lopez Bernal J, et al. Effectiveness of the Pfizer-BioNTech and Oxford-AstraZeneca Vaccines On Covid-19 Related Symptoms, Hospital Admissions, and Mortality in Older Adults in England: Test Negative Case-control Study. BMJ. 2021 05 13;373:n1088. PubMed PMID: 33985964.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Effectiveness of the Pfizer-BioNTech and Oxford-AstraZeneca vaccines on covid-19 related symptoms, hospital admissions, and mortality in older adults in England: test negative case-control study. AU - Lopez Bernal,Jamie, AU - Andrews,Nick, AU - Gower,Charlotte, AU - Robertson,Chris, AU - Stowe,Julia, AU - Tessier,Elise, AU - Simmons,Ruth, AU - Cottrell,Simon, AU - Roberts,Richard, AU - O'Doherty,Mark, AU - Brown,Kevin, AU - Cameron,Claire, AU - Stockton,Diane, AU - McMenamin,Jim, AU - Ramsay,Mary, Y1 - 2021/05/13/ PY - 2021/5/14/entrez PY - 2021/5/15/pubmed PY - 2021/5/21/medline SP - n1088 EP - n1088 JF - BMJ (Clinical research ed.) JO - BMJ VL - 373 N2 - OBJECTIVE: To estimate the real world effectiveness of the Pfizer-BioNTech BNT162b2 and Oxford-AstraZeneca ChAdOx1-S vaccines against confirmed covid-19 symptoms (including the UK variant of concern B.1.1.7), admissions to hospital, and deaths. DESIGN: Test negative case-control study. SETTING: Community testing for covid-19 in England. PARTICIPANTS: 156 930 adults aged 70 years and older who reported symptoms of covid-19 between 8 December 2020 and 19 February 2021 and were successfully linked to vaccination data in the National Immunisation Management System. INTERVENTIONS: Vaccination with BNT162b2 or ChAdOx1-S. MAIN OUTCOME MEASURES: Primary outcomes were polymerase chain reaction confirmed symptomatic SARS-CoV-2 infections, admissions to hospital for covid-19, and deaths with covid-19. RESULTS: Participants aged 80 years and older vaccinated with BNT162b2 before 4 January 2021 had a higher odds of testing positive for covid-19 in the first nine days after vaccination (odds ratio up to 1.48, 95% confidence interval 1.23 to 1.77), indicating that those initially targeted had a higher underlying risk of infection. Vaccine effectiveness was therefore compared with the baseline post-vaccination period. Vaccine effects were noted 10 to 13 days after vaccination, reaching a vaccine effectiveness of 70% (95% confidence interval 59% to 78%), then plateauing. From 14 days after the second dose a vaccination effectiveness of 89% (85% to 93%) was found compared with the increased baseline risk. Participants aged 70 years and older vaccinated from 4 January (when ChAdOx1-S delivery commenced) had a similar underlying risk of covid-19 to unvaccinated individuals. With BNT162b2, vaccine effectiveness reached 61% (51% to 69%) from 28 to 34 days after vaccination, then plateaued. With ChAdOx1-S, effects were seen from 14 to 20 days after vaccination, reaching an effectiveness of 60% (41% to 73%) from 28 to 34 days, increasing to 73% (27% to 90%) from day 35 onwards. On top of the protection against symptomatic disease, a further 43% (33% to 52%) reduced risk of emergency hospital admission and 51% (37% to 62%) reduced risk of death was observed in those who had received one dose of BNT162b2. Participants who had received one dose of ChAdOx1-S had a further 37% (3% to 59%) reduced risk of emergency hospital admission. Follow-up was insufficient to assess the effect of ChAdOx1-S on mortality. Combined with the effect against symptomatic disease, a single dose of either vaccine was about 80% effective at preventing admission to hospital with covid-19 and a single dose of BNT162b2 was 85% effective at preventing death with covid-19. CONCLUSION: Vaccination with either one dose of BNT162b2 or ChAdOx1-S was associated with a significant reduction in symptomatic covid-19 in older adults, and with further protection against severe disease. Both vaccines showed similar effects. Protection was maintained for the duration of follow-up (>6 weeks). A second dose of BNT162b2 was associated with further protection against symptomatic disease. A clear effect of the vaccines against the B.1.1.7 variant was found. SN - 1756-1833 UR - https://www.unboundmedicine.com/medline/citation/33985964/Effectiveness_of_the_Pfizer_BioNTech_and_Oxford_AstraZeneca_vaccines_on_covid_19_related_symptoms_hospital_admissions_and_mortality_in_older_adults_in_England:_test_negative_case_control_study_ L2 - http://www.bmj.com/lookup/pmidlookup?view=long&pmid=33985964 DB - PRIME DP - Unbound Medicine ER -