Of the 216 confirmed cases in the modified
vaccinated cohort, 6 occurred in the HZ/su
group and 210 in the placebo group after a mean
follow-up of 3.2 years (Table 2). The overall incidence
of herpes zoster per 1000 person-years
was 0.3 in the HZ/su group and 9.1 in the placebo
group, for an overall vaccine efficacy of 97.2%
(95% confidence interval [CI], 93.7 to 99.0;
P