Fig. 4

Frequency of true- and mock-immunized subjects experiencing systemic adverse events after each immunization 1–6. Number of local AEs (mild/moderate) experienced by each subject after true- and mock-immunizations 1–6. The numbers at the top of the graphs represent the number of individuals immunized at each immunization. The numbers at the top of each column represent the number of AEs/subject. The timing of each immunization is shown in Fig. 2