Table 3.
Impact of routine and catch-up herpes zoster vaccination on GP-diagnosed herpes zoster by time since cohorts were first eligible for vaccination
| Period | Age on 1 Sept 2013 (age when first eligible for vaccination) | Average cumulative uptake* | Expected events† | Observed events | Incidence rate ratio‡ (95% CI) |
Expected incidence per 1000 person-years | Incidence reduction per 1000 person-years (95% CI) |
Vaccine effectiveness§ (95% CI) |
| Routine cohorts | ||||||||
| First year after vaccine eligibility | 66–70 years | 47% | 1098 | 851 | 0.77 (0.72 to 0.83) | 8.24 | 1.87 (1.42 to 2.30) | 48% (37% to 59%) |
| (70–71 years) | ||||||||
| Second year after vaccine eligibility | 67–70 years | 64% | 838 | 509 | 0.61 (0.55 to 0.66) | 8.45 | 3.33 (2.85 to 3.76) | 61% (53% to 69%) |
| (70–71 years) | ||||||||
| Third year after vaccine eligibility | 68–70 years | 71% | 616 | 378 | 0.61 (0.55 to 0.68) | 8.66 | 3.36 (2.79 to 3.88) | 54% (45% to 63%) |
| (70–71 years) | ||||||||
| Fourth year after vaccine eligibility | 69–70 years | 75% | 413 | 217 | 0.52 (0.46 to 0.6) | 8.86 | 4.22 (3.55 to 4.80) | 63% (53% to 72%) |
| (70–71 years) | ||||||||
| Fifth year after vaccine eligibility | 70 years | 77% | 199 | 124 | 0.62 (0.52 to 0.74) | 9.05 | 3.42 (2.33 to 4.34) | 49% (33% to 62%) |
| (70–71 years) | ||||||||
| All years of the programme | 66–70 years | 62% | 3164 | 2079 | 0.66 (0.63 to 0.69) | 8.50 | 2.92 (2.66 to 3.18) | 55% (50% to 60%) |
| (70–71 years) | ||||||||
| Catch-up cohorts | ||||||||
| Second year after vaccine eligibility | 75–79 years | 62% | 757 | 481 | 0.63 (0.58 to 0.69) | 9.82 | 3.60 (3.00 to 4.14) | 59% (49% to 68%) |
| (78–80 years) | ||||||||
| Third year after vaccine eligibility | 77–79 years | 63% | 578 | 397 | 0.68 (0.62 to 0.76) | 9.95 | 3.14 (2.42 to 3.79) | 50% (38% to 60%) |
| (78–80 years) | ||||||||
| Fourth year after vaccine eligibility | 78–79 years | 63% | 409 | 273 | 0.67 (0.59 to 0.75) | 10.07 | 3.36 (2.51 to 4.13) | 53% (40% to 65%) |
| (78–80 years) | ||||||||
| Fifth year after vaccine eligibility | 79 years | 59% | 124 | 81 | 0.65 (0.52 to 0.81) | 10.18 | 3.54 (1.91 to 4.84) | 58% (32% to 80%) |
| (79–80 years) | ||||||||
| All years of the programme | 74–79 years | 57% | 2811 | 1950 | 0.69 (0.66 to 0.73) | 9.85 | 3.02 (2.68 to 3.34) | 53% (47% to 59%) |
| (78–80 years) | ||||||||
*Calculated by taking the mean of the cumulative uptake values in each month from October to September of the relevant years and cohorts.
†Expected if vaccine not introduced; based on model results for unvaccinated cohorts.
‡Estimated from the Poisson regression model with a log-linear time trend, quadratic age effect and the factor for vaccine eligibility.
§Effectiveness required to generate the observed reduction given the impact and coverage.
GP, general practice.