Table 4.
Impact of routine and catch-up herpes zoster vaccination on GP-diagnosed postherpetic neuralgia 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% | 151 | 103 | 0.67 (0.55 to 0.82) | 1.13 | 0.37 (0.20 to 0.51) | 70% (38% to 95%) |
| (70–71 years) | ||||||||
| Second year after vaccine eligibility | 67–70 years | 64% | 121 | 52 | 0.43 (0.32 to 0.56) | 1.22 | 0.70 (0.53 to 0.82) | 89% (68% to 100%) |
| (70–71 years) | ||||||||
| Third year after vaccine eligibility | 68–70 years | 71% | 93 | 46 | 0.49 (0.37 to 0.66) | 1.30 | 0.66 (0.45 to 0.83) | 71% (48% to 89%) |
| (70–71 years) | ||||||||
| Fourth year after vaccine eligibility | 69–70 years | 75% | 65 | 35 | 0.53 (0.38 to 0.75) | 1.39 | 0.65 (0.35 to 0.86) | 62% (34% to 82%) |
| (70–71 years) | ||||||||
| Fifth year after vaccine eligibility | 70 years | 77% | 32 | 12 | 0.37 (0.21 to 0.64) | 1.47 | 0.93 (0.52 to 1.17) | 82% (46% to 100%) |
| (70–71 years) | ||||||||
| All years of the programme | 66–70 years | 62% | 461 | 248 | 0.53 (0.46 to 0.61) | 1.24 | 0.58 (0.49 to 0.66) | 75% (63% to 86%) |
| (70–71 years) | ||||||||
| Catch-up cohorts | ||||||||
| First year after vaccine eligibility | 74–79 years | 48% | 174 | 133 | 0.76 (0.63 to 0.90) | 1.78 | 0.44 (0.18 to 0.65) | 51% (21% to 77%) |
| (78–80 years) | ||||||||
| Second year after vaccine eligibility | 75–79 years | 62% | 143 | 87 | 0.60 (0.48 to 0.74) | 1.86 | 0.75 (0.48 to 0.96) | 64% (41% to 83%) |
| (78–80 years) | ||||||||
| Third year after vaccine eligibility | 77–79 years | 63% | 112 | 48 | 0.42 (0.32 to 0.56) | 1.93 | 1.12 (0.84 to 1.32) | 91% (69% to 100%) |
| (78–80 years) | ||||||||
| Fourth year after vaccine eligibility | 78–79 years | 63% | 81 | 55 | 0.67 (0.51 to 0.88) | 2.00 | 0.66 (0.25 to 0.98) | 53% (20% to 78%) |
| (78–80 years) | ||||||||
| Fifth year after vaccine eligibility | 79 years | 59% | 25 | 13 | 0.51 (0.30 to 0.88) | 2.06 | 1.01 (0.24 to 1.45) | 82% (20% to 100%) |
| (79–80 years) | ||||||||
| All years of the programme | 74–79 years | 57% | 536 | 336 | 0.62 (0.55 to 0.69) | 1.88 | 0.71 (0.59 to 0.84) | 66% (54% to 78%) |
| (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 quadratic 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.