Fig. 2: Results of linear mixed effects regression model fit to vaccine effectiveness data against severe COVID-19 extracted from our systematic review.

Vaccine effectiveness data against severe COVID-19 (points and whiskers for 95% CI) are shown for pre-Delta (top row, panels (A)–(D), Delta (middle row, panels (E)–(H)) and Omicron (bottom row, panels (I)–(L)) variants. Note that for panels (D) and (I), no effectiveness data was available. Opacity indicates the degree of confidence in the data as determined by the width of the confidence interval. Predicted vaccine effectiveness using a linear mixed effects regression model (solid lines) and 95% confidence intervals (shaded area) are overlaid. The figure shows effectiveness following mRNA-1273 (red), BNT162b2 (blue), any mRNA (purple) and ChAdOx-nCov-1 (pink) vaccination.