McKeigue, P., McAllister, D., Caldwell, D., Gribben, C., Bishop, J., McGurnaghan, S., Armstrong, M., Delvaux, J., Colville, S., Hutchinson, S., Robertson, C., Lone, N. & Colhoun, H. 2021, 'Relation of severe COVID-19 in Scotland to transmission-related factors and risk conditions eligible for shielding support: REACT-SCOT case-control study', BMC Medicine, 19, article no: 149. https://doi.org/10.1186/s12916-021-02021-5