Sheikh, A., Kerr, S., Woolhouse, M., McMenamin, J., Robertson, C., , , Simpson, C. R., Millington, T., Shi, T., Agrawal, U., Shahul Hameed, S., Hall, E., Rudan, I., Shah, S. A., Ritchie, L., Stock, S., & McCowan, C. (2022). severity of omicron variant of concern and effectiveness of vaccine boosters against symptomatic disease in Scotland (EAVE II): a national cohort study with nested test-negative design. Lancet infectious diseases, 22(7), 959–966. http://access.bl.uk/ark:/81055/vdc_100158012903.0x00003a