To evaluate the effectiveness and safety of vaccination for preventing herpes zoster in older adults, altogether 24 RCTs with 88,531 participants were analyzed in a Cochrane systematic review «Gagliardi AM, Andriolo BN, Torloni MR ym. Vaccines...»1. Fifteen studies used live attenuated varicella zoster virus (VZV) vaccines. Nine studies tested recombinant zoster vaccine (RZV).
The incidence of herpes zoster, at up to three years of follow‐up, was lower in participants who received the LZV vaccine than in those who received a placebo: risk ratio (RR) 0.49; 95 % confidence interval (CI) 0.43 to 0.56, risk difference (RD) 2 %, number needed to treat to benefit (NNTB) 50; GRADE: moderate quality evidence. The vaccinated group had a higher incidence of mild to moderate intensity adverse events. These date came from one large study that included 38,546 people aged 60 years or older.
Two studies including 22,022 participants compared the RZV vaccine to the placebo; the group that received the new vaccine had a lower incidence of herpes zoster at 3.2 years of follow‐up: RR 0.08, 95 % CI 0.03 to 0.23, RD 3 %, NNTB 33; GRADE: moderate quality evidence. The vaccinated group had a higher incidence of adverse events but most them were of mild to moderate intensity.