1. Robust humoral and cellular recall responses to AZD1222 attenuate breakthrough SARS-CoV-2 infection compared to unvaccinated.
- Author
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Maaske, Jill, Sproule, Stephanie, Falsey, Ann R., Sobieszczyk, Magdalena E., Luetkemeyer, Anne F., Paulsen, Grant C., Riddler, Sharon, Robb, Merlin L., Rolle, Charlotte-Paige, Sha, Beverly E., Tina Tong, Ahani, Bahar, Aksyuk, Anastasia A., Bansa, Himanshu, Egan, Timothy, Jepson, Brett, Padilla, Marcelino, Pate, Nirmeshkumar, Shoemaker, Kathryn, and Stanley, Ann Marie
- Subjects
VIRAL shedding ,SARS-CoV-2 ,BREAKTHROUGH infections ,COVID-19 ,COVID-19 vaccines ,VACCINATION ,CORONAVIRUS diseases - Abstract
Background: Breakthrough severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in coronavirus disease 2019 (COVID-19) vaccinees typically produces milder disease than infection in unvaccinated individuals. Methods: To explore disease attenuation, we examined COVID-19 symptom burden and immuno-virologic responses to symptomatic SARS-CoV-2 infection in participants (AZD1222: n=177/17,617; placebo: n=203/8,528) from a 2:1 randomized, placebo-controlled, phase 3 study of two-dose primary series AZD1222 (ChAdOx1 nCoV-19) vaccination (NCT04516746). Results: We observed that AZD1222 vaccinees had an overall lower incidence and shorter duration of COVID-19 symptoms compared with placebo recipients, as well as lower SARS-CoV-2 viral loads and a shorter median duration of viral shedding in saliva. Vaccinees demonstrated a robust antibody recall response versus placebo recipients with low-to-moderate inverse correlations with virologic endpoints. Vaccinees also demonstrated an enriched polyfunctional spike-specific Th-1-biased CD4+ and CD8+ T-cell response that was associated with strong inverse correlations with virologic endpoints. Conclusion: Robust immune responses following AZD1222 vaccination attenuate COVID-19 disease severity and restrict SARS-CoV-2 transmission potential by reducing viral loads and the duration of viral shedding in saliva. Collectively, these analyses underscore the essential role of vaccination in mitigating the COVID-19 pandemic. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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