Omicron infection following vaccination enhances a broad spectrum of immune responses dependent on infection history
Hailey Hornsby, Alexander R. Nicols, Stéphanie Longet, Chang Liu, Adriana Tomić, Adrienn Angyal, Barbara Kronsteiner, Jessica K. Tyerman, Tom Tipton, Peijun Zhang, Marta Gallis, Piyada Supasa, Muneeswaran Selvaraj, Priyanka Abraham, Isabel Neale, Mohammad Ali, Natalie A. Barratt, Jeremy Nell, Lotta Gustafsson, Scarlett Strickland, Irina Grouneva, Timothy Rostron, Shona C. Moore, Luisa M. Hering, Susan L. Dobson, Sagida Bibi, Juthathip Mongkolsapaya, Teresa Lambe, Dan Wootton, Victoria Hall, Susan Hopkins, Tao Dong, Eleanor Barnes, Gavin Screaton, Alex Richter, Lance Turtle, Sarah Rowland‐Jones, Miles W. Carroll, C.J. Duncan, Paul Klenerman, Susanna Dunachie, Rebecca Payne, Thushan I. de Silva
Abstract
Abstract Pronounced immune escape by the SARS-CoV-2 Omicron variant has resulted in many individuals possessing hybrid immunity, generated through a combination of vaccination and infection. Concerns have been raised that omicron breakthrough infections in triple-vaccinated individuals result in poor induction of omicron-specific immunity, and that prior SARS-CoV-2 infection is associated with immune dampening. Taking a broad and comprehensive approach, we characterize mucosal and blood immunity to spike and non-spike antigens following BA.1/BA.2 infections in triple mRNA-vaccinated individuals, with and without prior SARS-CoV-2 infection. We find that most individuals increase BA.1/BA.2/BA.5-specific neutralizing antibodies following infection, but confirm that the magnitude of increase and post-omicron titres are higher in the infection-naive. In contrast, significant increases in nasal responses, including neutralizing activity against BA.5 spike, are seen regardless of infection history. Spike-specific T cells increase only in infection-naive vaccinees; however, post-omicron T cell responses are significantly higher in the previously-infected, who display a maximally induced response with a highly cytotoxic CD8+ phenotype following their 3 rd mRNA vaccine dose. Responses to non-spike antigens increase significantly regardless of prior infection status. These findings suggest that hybrid immunity induced by omicron breakthrough infections is characterized by significant immune enhancement that can help protect against future omicron variants.