Table 6.

Impact of routine and catch-up herpes zoster vaccination on hospitalised 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 10 000 person-years	Incidence reduction per 10 000 person-years (95% CI)	Vaccine effectiveness§ (95% CI)
Routine cohorts
First year after vaccine eligibility	66–70 years	47%	204	154	0.75 (0.64 to 0.88)	0.73	0.18 (0.08 to 0.27)	53% (25% to 77%)
	(70–71 years)
Second year after vaccine eligibility	67–70 years	64%	170	133	0.78 (0.65 to 0.93)	0.84	0.19 (0.06 to 0.29)	34% (11% to 54%)
	(70–71 years)
Third year after vaccine eligibility	68–70 years	71%	143	92	0.64 (0.52 to 0.79)	0.97	0.35 (0.21 to 0.47)	51% (30% to 68%)
	(70–71 years)
Fourth year after vaccine eligibility	69–70 years	75%	108	63	0.58 (0.45 to 0.75)	1.12	0.47 (0.28 to 0.62)	56% (34% to 73%)
	(70–71 years)
Fifth year after vaccine eligibility	70 years	77%	57	30	0.52 (0.36 to 0.75)	1.28	0.61 (0.32 to 0.82)	62% (32% to 83%)
	(70–71 years)
All years of the programme	66–70 years	62%	682	472	0.69 (0.62 to 0.77)	0.89	0.27 (0.21 to 0.33)	50% (38% to 61%)
	(70–71 years)
Catch-up cohorts
First year after vaccine eligibility	74–79 years	48%	343	274	0.80 (0.70 to 0.90)	1.68	0.34 (0.16 to 0.5)	42% (20% to 62%)
	(78–80 years)
Second year after vaccine eligibility	75–79 years	62%	303	191	0.63 (0.54 to 0.73)	1.88	0.7 (0.51 to 0.86)	60% (44% to 74%)
	(78–80 years)
Third year after vaccine eligibility	77–79 years	63%	252	176	0.69 (0.59 to 0.81)	2.08	0.63 (0.39 to 0.84)	48% (30% to 64%)
	(78–80 years)
Fourth year after vaccine eligibility	78–79 years	63%	192	141	0.73 (0.61 to 0.87)	2.28	0.62 (0.3 to 0.89)	43% (21% to 62%)
	(78–80 years)
Fifth year after vaccine eligibility	79 years	59%	60	38	0.62 (0.45 to 0.86)	2.45	0.93 (0.34 to 1.35)	64% (24% to 93%)
	(79–80 years)
All years of the programme	74–79 years	57%	1150	820	0.72 (0.66 to 0.78)	1.93	0.55 (0.43 to 0.66)	49% (38% 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 quadratic time trend, cubic age effect, and the factor for vaccine eligibility.

§Effectiveness required to generate the observed reduction given the impact and coverage.