Peak timing: effect of vaccination campaigns. Difference in the median peak weeks in the reference stochastic forecast output (SFO) set with mass vaccination campaigns and the reference SFO set as a function of the median peak week in the reference SFO set, for the 500 busiest airports of the world. Dots are color-coded according to the corresponding airport's climatic zone. In the inset, we show the box plot indicating the distribution of the differences (in days) between the peak weeks of the two SFO sets. The differences were all limited to the minimal time scale used in the model (1 day) and thus were indistinguishable from stochastic fluctuations.