Specific and off-target immune responses following COVID-19 vaccination with ChAdOx1-S and BNT162b2 vaccines—an exploratory sub-study of the BRACE trial
Nicole L. Messina, Susie Germano, Rebecca McElroy, Rhian Bonnici, Branka Grubor‐Bauk, David J. Lynn, Ellie McDonald, Suellen Nicholson, Kirsten P. Perrett, Laure F. Pittet, Rajeev Rudraraju, Natalie E. Stevens, Kanta Subbarao, Nigel Curtis, Nigel Curtis, Nigel Curtis, Andrew Davidson, Kaya Gardiner, Amanda Gwee, Tenaya Jamieson, Nicole Messina, Nicole Messina, Thilanka Morawakage, Susan Perlen, Kirsten Perrett, Laure Pittet, Amber Sastry, Jia Wei Teo, Francesca Orsini, Katherine Lee, Cecilia Moore, Suzanna Vidmar, Laure Pittet, Rashida Ali, Ross Dunn, Peta Edler, Grace Gell, Casey Goodall, Richard Hall, Ann Krastev, Nathan La, Ellie McDonald, Nick McPhate, Thao Nguyen, Jack Ren, Luke Stevens, Nicole Messina, Nicole Messina, Ahmed Alamrousi, Rhian Bonnici, Thanh Dang, Susie Germano, Jenny Hua, Rebecca McElroy, Monica Razmovska, Scott Reddiex, Xiaofang Wang, Jeremy Anderson, Kristy Azzopardi, Vicki Bennett-Wood, Anna Czajko, Nadia Mazarakis, Conor McCafferty, Frances Oppedisano, Belinda Ortika, Casey Pell, Leena Spry, Ryan Toh, Sunitha Velagapudi, Amanda Vlahos, Ashleigh Wee-Hee, Pedro Ramos, Karina De La Cruz, Dinusha Gamage, Anushka Karunanayake, Isabella Mezzetti, Benjamin Ong, Ronita Singh, Enoshini Sooriyarachchi, Suellen Nicholson, Natalie Cain, Rianne Brizuela, Han Huang, Veronica Abruzzo, Morgan Bealing, Patricia Bimboese, Kirsty Bowes, Emma Burrell, Joyce Chan, Jac Cushnahan, Hannah Elborough, Olivia Elkington, Kieran Fahey, Monique Fernandez, Catherine Flynn, Sarah Fowler, Marie Gentile Andrit, Bojana Gladanac, Catherine Hammond, Norine Ma
Abstract
BACKGROUND: The COVID-19 pandemic led to the rapid development and deployment of several highly effective vaccines against SARS-CoV-2. Recent studies suggest that these vaccines may also have off-target effects on the immune system. We sought to determine and compare the off-target effects of the adenovirus vector ChAdOx1-S (Oxford-AstraZeneca) and modified mRNA BNT162b2 (Pfizer-BioNTech) vaccines on immune responses to unrelated pathogens. METHODS: Prospective sub-study within the BRACE trial. Blood samples were collected from 284 healthcare workers before and 28 days after ChAdOx1-S or BNT162b2 vaccination. SARS-CoV-2-specific antibodies were measured using ELISA, and whole blood cytokine responses to specific (SARS-CoV-2) and unrelated pathogen stimulation were measured by multiplex bead array. FINDINGS: Both vaccines induced robust SARS-CoV-2 specific antibody and cytokine responses. ChAdOx1-S vaccination increased cytokine responses to heat-killed (HK) Candida albicans and HK Staphylococcus aureus and decreased cytokine responses to HK Escherichia coli and BCG. BNT162b2 vaccination decreased cytokine response to HK E. coli and had variable effects on cytokine responses to BCG and resiquimod (R848). After the second vaccine dose, BNT162b2 recipients had greater specific and off-target cytokine responses than ChAdOx1-S recipients. INTERPRETATION: ChAdOx1-S and BNT162b2 vaccines alter cytokine responses to unrelated pathogens, indicative of potential off-target effects. The specific and off-target effects of these vaccines differ in their magnitude and breadth. The clinical relevance of these findings is uncertain and needs further study. FUNDING: Bill & Melinda Gates Foundation, National Health and Medical Research Council, Swiss National Science Foundation and the Melbourne Children's. BRACE trial funding is detailed in acknowledgements.