COVID-19 vaccine effectiveness against hospitalisation and death of people in clinical risk groups during the Delta variant period: English primary care network cohort study

Heather J Whitaker; Ruby S M Tsang; Rachel Byford; Carole Aspden; Elizabeth Button; Praveen Sebastian Pillai; Gavin Jamie; Debasish Kar; John Williams; Mary Sinnathamby; Gemma Marsden; William H Elson; Meredith Leston; Sneha Anand; Cecilia Okusi; Xuejuan Fan; Ezra Linley; Cathy Rowe; Silvia DArcangelo; Ashley D Otter; Joanna Ellis; F D Richard Hobbs; Victoria Tzortziou-Brown; Maria Zambon; Mary Ramsay; Kevin E Brown; Gayatri Amirthalingam; Nick J Andrews; Simon de Lusignan; Jamie Lopez Bernal

doi:10.1016/j.jinf.2023.08.005

COVID-19 vaccine effectiveness against hospitalisation and death of people in clinical risk groups during the Delta variant period: English primary care network cohort study

J Infect. 2023 Oct;87(4):315-327. doi: 10.1016/j.jinf.2023.08.005. Epub 2023 Aug 12.

Authors

Heather J Whitaker¹, Ruby S M Tsang², Rachel Byford², Carole Aspden², Elizabeth Button², Praveen Sebastian Pillai³, Gavin Jamie², Debasish Kar², John Williams², Mary Sinnathamby⁴, Gemma Marsden⁵, William H Elson², Meredith Leston², Sneha Anand², Cecilia Okusi², Xuejuan Fan², Ezra Linley⁶, Cathy Rowe⁷, Silvia DArcangelo⁷, Ashley D Otter⁷, Joanna Ellis⁸, F D Richard Hobbs², Victoria Tzortziou-Brown⁵, Maria Zambon³, Mary Ramsay⁴, Kevin E Brown⁴, Gayatri Amirthalingam⁴, Nick J Andrews⁹, Simon de Lusignan¹⁰, Jamie Lopez Bernal¹¹

Affiliations

¹ Statistics, Modelling and Economics Department, UK Health Security Agency, 61 Colindale Avenue, London NW9 5EQ, UK.
² Nuffield Department of Primary Care Health Sciences, University of Oxford, Oxford OX2 6GG, UK.
³ Virus Reference Laboratory, UK Health Security Agency, 61 Colindale Avenue, London NW9 5EQ, UK.
⁴ Immunisation and Vaccine Preventable Diseases Division, UK Health Security Agency, 61 Colindale Avenue, London NW9 5EQ, UK.
⁵ Royal College of General Practitioners Research and Surveillance Centre, Euston Square, London NW1 2FB, UK.
⁶ Vaccine Evaluation Unit, UK Health Security Agency, Manchester M13 9WL, UK.
⁷ Diagnostics and Genomics, UK Health Security Agency, Porton Down, Salisbury SP4 0JG, UK.
⁸ Immunisation and Vaccine Preventable Diseases Division, UK Health Security Agency, 61 Colindale Avenue, London NW9 5EQ, UK; Virus Reference Laboratory, UK Health Security Agency, 61 Colindale Avenue, London NW9 5EQ, UK.
⁹ Statistics, Modelling and Economics Department, UK Health Security Agency, 61 Colindale Avenue, London NW9 5EQ, UK; Immunisation and Vaccine Preventable Diseases Division, UK Health Security Agency, 61 Colindale Avenue, London NW9 5EQ, UK.
¹⁰ Nuffield Department of Primary Care Health Sciences, University of Oxford, Oxford OX2 6GG, UK; Royal College of General Practitioners Research and Surveillance Centre, Euston Square, London NW1 2FB, UK.
¹¹ Immunisation and Vaccine Preventable Diseases Division, UK Health Security Agency, 61 Colindale Avenue, London NW9 5EQ, UK. Electronic address: jamie.lopezbernal2@ukhsa.gov.uk.

PMID: 37579793
DOI: 10.1016/j.jinf.2023.08.005

Abstract

Background: COVID-19 vaccines have been shown to be highly effective against hospitalisation and death following COVID-19 infection. COVID-19 vaccine effectiveness estimates against severe endpoints among individuals with clinical conditions that place them at increased risk of critical disease are limited.

Methods: We used English primary care medical record data from the Oxford-Royal College of General Practitioners Research and Surveillance Centre sentinel network (N > 18 million). Data were linked to the National Immunisation Management Service database, Second Generation Surveillance System for virology test data, Hospital Episode Statistics, and death registry data. We estimated adjusted vaccine effectiveness (aVE) against COVID-19 infection followed by hospitalisation and death among individuals in specific clinical risk groups using a cohort design during the delta-dominant period. We also report mortality statistics and results from our antibody surveillance in this population.

Findings: aVE against severe endpoints was high, 14-69d following a third dose aVE was 96.4% (95.1%-97.4%) and 97.9% (97.2%-98.4%) for clinically vulnerable people given a Vaxzevria and Comirnaty primary course respectively. Lower aVE was observed in the immunosuppressed group: 88.6% (79.1%-93.8%) and 91.9% (85.9%-95.4%) for Vaxzevria and Comirnaty respectively. Antibody levels were significantly lower among the immunosuppressed group than those not in this risk group across all vaccination types and doses. The standardised case fatality rate within 28 days of a positive test was 3.9/1000 in people not in risk groups, compared to 12.8/1000 in clinical risk groups. Waning aVE with time since 2nd dose was also demonstrated, for example, Comirnaty aVE against hospitalisation reduced from 96.0% (95.1-96.7%) 14-69days post-dose 2-82.9% (81.4-84.2%) 182days+ post-dose 2.

Interpretation: In all clinical risk groups high levels of vaccine effectiveness against severe endpoints were seen. Reduced vaccine effectiveness was noted among the immunosuppressed group.

Keywords: Antibody; COVID-19; Clinical risk; Immunosuppression; Mortality; SARS-CoV-2; Vaccine effectiveness.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

BNT162 Vaccine
COVID-19 Vaccines*
COVID-19* / prevention & control
ChAdOx1 nCoV-19
Cohort Studies
Hospitalization
Humans
Primary Health Care
SARS-CoV-2
Vaccine Efficacy

Substances

COVID-19 Vaccines
BNT162 Vaccine
ChAdOx1 nCoV-19

Supplementary concepts

SARS-CoV-2 variants