@article{Katikireddi_S-2021_51152,
title = {Two-dose ChAdOx1 nCoV-19 vaccine protection against COVID-19 hospital admissions and deaths over time: a retrospective, population-based cohort study in Scotland and Brazil},
author = {Katikireddi, S. and Cerqueira-Silva, T. and Vasileiou, E. and Robertson, C. and Amele, S. and Pan, J. and Taylor, B. and Boaventura, V. and Werneck, G. and Flores-Ortiz, R. and Agrawal, U. and Docherty, A. and McCowan, C. and McMenamin, J. and Moore, E. and Ritchie, L. and Rudan, I. and Shah, S. and Shi, T. and Simpson, C. and Barreto, M. and de Araújo Oliveira, V. and Barral-Netto, M. and Sheikh, A.},
month = {dec},
year = {2021},
abstract = {BackgroundReports suggest that COVID-19 vaccine effectiveness is decreasing, but whether this reflects waning or new SARS-CoV-2 variants—especially delta (B.1.617.2)—is unclear. We investigated the association between time since two doses of ChAdOx1 nCoV-19 vaccine and risk of severe COVID-19 outcomes in Scotland (where delta was dominant), with comparative analyses in Brazil (where delta was uncommon).},
pages = {25-35},
volume = {399},
issue = {10319},
journal = {The Lancet},
publisher = {Elsevier},
url = {https://doi.org/10.1016/S0140-6736(21)02754-9},
}
