Severity of BA.2 variant and vaccine effectiveness against symptomatic disease in Scotland

Kerr, Steven and Robertson, Chris and Hillman, Sam and Grange, Zoe and Sullivan, Christopher and Sheikh, Aziz (2022) Severity of BA.2 variant and vaccine effectiveness against symptomatic disease in Scotland. The Lancet Regional Health - Europe, 23. 100533. ISSN 2666-7762 (

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The first confirmed case of SARS-CoV-2 omicron BA.2 was identified in Scotland on December 23, 2021.1 BA.2 was the dominant variant in Scotland, replacing omicron BA.1.1.529 (BA.1) and accounting for >90% of new cases as of March 23, 2022 (Fig. S1, Supplementary Appendix).1 Initial research suggested that BA.2 was associated with an increase in the odds ratio of infection for both unvaccinated and fully vaccinated individuals compared to BA.1.2 Since then, other studies from Qatar haveshownthatvaccinationcanprovideprotectionagainst symptomatic BA.1 and BA.2 infection,3 but vaccination effectiveness is stronger after a third ‘booster’ dose. We undertook a test-negative design (TND) study of all individuals over the age of 18in Scotland whohadaRT-PCR test for SARS-CoV-2 from the community, were symptomatic at time of test, had their sample virally sequenced between November 1, 2021 and March 20, 2022, and did not have a record of a previous positive test using the Early Pandemic Evaluation and Enhanced Surveillance (EAVE II) platform.