Hall, V., Foulkes, S., Saei, A., Andrews, N., Oguti, B., Charlett, A., Wellington, E., Stowe, J., Gillson, N., Atti, A., Islam, J., Karagiannis, I., Munro, K., Khawam, J., Chand, M., Brown, C., Ramsay, M., Lopez-Bernal, J., Hopkins, S. & SIREN Study Group 2021, 'COVID-19 vaccine coverage in health-care workers in England and effectiveness of BNT162b2 mRNA vaccine against infection (SIREN): a prospective, multicentre, cohort study', The Lancet, 397(10286), pp. 1725-1735. https://doi.org/10.1016/S0140-6736(21)00790-X