Thiruvengadam R, Awasthi A, Medigeshi G, Bhattacharya S, et al. Effectiveness of ChAdOx1 nCoV-19 vaccine against SARS-CoV-2 infection during the
delta (B.1.617.2) variant surge in India: a test-negative, case-control study and
a mechanistic study of post-vaccination immune responses. Lancet Infect Dis 2021 Nov 25. pii: S1473-3099(21)00680.
PMID: 34838183