Among all subjects aged 50 years or older in the mTVC, no cases of PHN were reported in the vaccine group compared with 18 cases reported in the placebo group.
14.2 Efficacy in Subjects 70 Years and Older
Study 2 was a randomized, placebo-controlled, observer-blind clinical study conducted in 18 countries. Randomization was stratified (3:1) by age: 70 to 79 years and ≥80 years. With the exception of age, the study exclusion criteria were the same as for Study 1. Subjects were followed for the development of HZ and PHN for a median of 3.9 years (range: 0 to 4.5 years). Suspected HZ cases were followed prospectively for the development of PHN as for Study 1.
The primary efficacy analysis population (mTVC) included 13,163 subjects aged 70 years and older who received 2 doses (0 and 2 months) of either SHINGRIX (n = 6,541) or placebo (n = 6,622) and did not develop a confirmed case of HZ within 1 month after the second dose. In the mTVC population, 54.7% were female; 77.6% were white, 17.1% were Asian, 1.0% were black, and 4.2% were of other racial/ethnic groups. The mean age of subjects was 75.5 years.
Confirmed HZ cases were determined by either PCR (92.3%) or by a Clinical eva luation Committee (7.7%).
Efficacy against Herpes Zoster
Vaccine efficacy results against HZ in subjects 70 years and older are shown in Table 3.
Table 3. Efficacy of SHINGRIX on Incidence of Herpes Zoster Compared with Placebo in Study 2a (mTVCb)
Age Group (Years)
SHINGRIX
Placebo
% Efficacy (95% CI)
N
n
Incidence Rate of HZ per 1,000 Person-Years
N
n
Incidence Rate of HZ per 1,000 Person-Years
Overall (≥70)c
6,541
23
0.9
6,622
223
9.2
89.8
(84.3, 93.7)
70 - 79
5,114
17
0.9
5,189
169
8.8
90.0
(83.5, 94.3)
≥80
1,427
6
1.2
1,433
54
11.0
89.1
(74.7, 96.2)
N = Number of subjects included in each group; n = Number of subjects having at least 1 confirmed HZ episode; HZ = Herpes zoster; CI = Confidence Interval.
a Study 2: NCT01165229.
b mTVC = Modified Total Vaccinated Cohort defined as subjects who received 2 doses (0 and 2 months) of either SHINGRIX or placebo and did not develop a confirmed case of HZ within 1 month after the second dose.
c Primary study endpoint was based on confirmed HZ cases in subjects aged 70 years and older.
In a descriptive analysis, vaccine efficacy against HZ in subjects 70 years and older was 85.1% (95% CI: 64.5, 94.8) in the fourth year after vaccination.
Efficacy against PHN
Among all subjects aged 70 years or older in the mTVC, 4 cases of PHN were reported in the vaccine group, compared with 28 cases reported in the placebo group. Vaccine efficacy against PHN was 85.5% (95% CI: [58.5; 96.3]). The benefit of SHINGRIX in the prevention of PHN can be attributed to the effect of the vaccine on the prevention of HZ.
Reduction of Use of Pain Medication
Among subjects with confirmed HZ, the use of HZ-associated pain medications was reported for 10 of 23 subjects (43.5%) who received SHINGRIX and for 160 of 223 subjects (71.7%) who received placebo.
14.3 Pooled Efficacy Analyses across Studies 1 and 2
The efficacy of SHINGRIX to prevent HZ and PHN in subjects 70 years and older was eva luated by combining the results from Studies 1 and 2 through a pre-specified pooled analysis in the mTVC. A total of 8,250 and 8,346 subjects who received SHINGRIX and placebo, respectively, were included i
