An Observational Cohort Study on the Incidence of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Infection and B.1.1.7 Variant Infection in Healthcare Workers by Antibody and Vaccination Status
Sheila Lumley, Gillian Rodger, Bede Constantinides, Nicholas Sanderson, Kevin Chau, Teresa Street, Denise O’Donnell, Alison Howarth, Stephanie B. Hatch, Brian D. Marsden, Stuart Cox, Tim James, Fiona C Warren, Liam J Peck, Thomas Ritter, Zoe de Toledo, Laura Warren, David Axten, Richard J. Cornall, E. Yvonne Jones, David I. Stuart, Gavin Screaton, Daniel Ebner, Sarah Hoosdally, Meera Chand, Derrick W. Crook, Anne-Marie O’Donnell, Christopher P. Conlon, Koen B. Pouwels, A. Sarah Walker, Tim E A Peto, Susan Hopkins, A Sarah Walker, Nicole Stoesser, Philippa C. Matthews, Katie Jeffery, David W. Eyre, Afrah Shibu, Aisling Curtis, Alexandra Mighiu, Ali Manji, Andrey Nezhentsev, Arun Somanathan, Beinn Khulusi, Ben Holloway, Caitlin Rigler, Charis Virgo, Charlotte Fields, Charlotte Lee, Elizabeth R. Daly, Elizabeth Hatton, Esme Weeks, Euan J McGivern, G Economides, Hannah E. Fuchs, Harry Jackson-Smith, Heather Tong, Helen Callard, Helen Clay, Henrietta Davies, Isaac Jarratt Barnham, Ishta Sharma, Jack Wilson, Jocelyn Ward, Joseph Cutteridge, Julia Kotowska, Kirsten Lee, Krupa Ravi, Laura Wilkins, Lottie Cansdale, Lucy Bland, Luiza Farache Trajano, M Chmura, Maria Lucey, Maria Pikoula, Meirian Evans, Molly Abbott, Morwenna Tamblyn, Oriane Grant, Rebecca Conway-Jones, Ross Toward, Roxanna E. Abhari, Ruby Wolman, Sara Hosseinzadeh, Sarah Thomas, Tara Madsen, Thomas Foord, Thomas Johnson, Vimukthi Perera, Zamin Shabir, Thomas Christott, George Doherty, Philip W. Fowler, Fredrik Karpe, James Kavanagh, Lucas Martins Ferreira, Matt J. Neville, Hayleah Pickford, Donal Skelly, Jeremy Swann
Abstract
BACKGROUND: Natural and vaccine-induced immunity will play a key role in controlling the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic. SARS-CoV-2 variants have the potential to evade natural and vaccine-induced immunity. METHODS: In a longitudinal cohort study of healthcare workers (HCWs) in Oxfordshire, United Kingdom, we investigated the protection from symptomatic and asymptomatic polymerase chain reaction (PCR)-confirmed SARS-CoV-2 infection conferred by vaccination (Pfizer-BioNTech BNT162b2, Oxford-AstraZeneca ChAdOx1 nCOV-19) and prior infection (determined using anti-spike antibody status), using Poisson regression adjusted for age, sex, temporal changes in incidence and role. We estimated protection conferred after 1 versus 2 vaccinations and from infections with the B.1.1.7 variant identified using whole genome sequencing. RESULTS: In total, 13 109 HCWs participated; 8285 received the Pfizer-BioNTech vaccine (1407 two doses), and 2738 the Oxford-AstraZeneca vaccine (49 two doses). Compared to unvaccinated seronegative HCWs, natural immunity and 2 vaccination doses provided similar protection against symptomatic infection: no HCW vaccinated twice had symptomatic infection, and incidence was 98% lower in seropositive HCWs (adjusted incidence rate ratio 0.02 [95% confidence interval {CI} < .01-.18]). Two vaccine doses or seropositivity reduced the incidence of any PCR-positive result with or without symptoms by 90% (0.10 [95% CI .02-.38]) and 85% (0.15 [95% CI .08-.26]), respectively. Single-dose vaccination reduced the incidence of symptomatic infection by 67% (0.33 [95% CI .21-.52]) and any PCR-positive result by 64% (0.36 [95% CI .26-.50]). There was no evidence of differences in immunity induced by natural infection and vaccination for infections with S-gene target failure and B.1.1.7. CONCLUSIONS: Natural infection resulting in detectable anti-spike antibodies and 2 vaccine doses both provide robust protection against SARS-CoV-2 infection, including against the B.1.1.7 variant.