A public health and budget impact analysis of vaccinating the elderly and at-risk adults with the 23-valent pneumococcal polysaccharide vaccine or 13-valent pneumococcal conjugate vaccine in the UK

Figures & data

Figure 1. Model schematics.

Figure 2. Model structure.

Figure 3. Epidemiological change in incidence of invasive pneumococcal disease induced by routine childhood immunization.

Table 1. Clinical and demographical parameters.

Parameter	Base case values	Ref.
Incidence of IPD	See Figure 3.	[6,40,46]
Proportions of the target population in each risk group	18–64 years AR i.c.: 7.3%/ AR i.s.: 0.9% ≥65 years AR i.c.: 60.5%/ AR i.s.: 2.3%	[41]
Risk of developing IPD (compared with the adult population)	18–44 years AR i.c.: 4.954/ AR i.s.: 1.168 ≥65 years AR i.c.: 10.157/ AR i.s.: 5.354	[41]
Herd protection effect: decrease in incidence of IPD associated with PCV serotypes (cumulative gamma distribution)^†	18–44 years α: 1.3048; β: 1.3117 (R^2 = 1.00) 45-64 years α: 0.7367; β: 2.4500 (R^2 = 0.98) ≥65 years α: 1.1766; β: 1.8131 (R^2 = 0.99)	[6,40]
Serotype replacement effect: increase in incidence of IPD associated with non-PCV serotypes (cumulative gamma distribution)^†	18–64 years No change ≥65 years α: 1.2986; β: 3.2196 (R^2 = 0.87)	[6,40]
Incidence of NBPP by age group (per 100,000 person-years)	18–44: 37.8 45–64: 84.4 65–74: 220.6 75–84: 420.3 ≥85: 856.6	[44,45]
Proportion of meningitis in IPD	5.1%	[42]
Proportion of meningitis patients with PMS	31.7%	[43]
Case–fatality rate by age group: IPD	18–64: 10.2% ≥65: 31.5%	[41]
Case–fatality rate: NBPP	3.1%	[44,45]

^†The change in the incidence of IPD in adults is estimated as where Γ is gamma function, γ is the lower incomplete Γ function and x is the cumulative vaccination rate in infants and children.

AR: At-risk adults; i.c.: Immunocompetent; i.s.: Immunosuppressed; IPD: Invasive pneumococcal disease; NBPP: Non-bacteremic pneumococcal pneumonia; PMS: Post-meningitis sequelae.

Table 2. Vaccine coverage rate.

	2005/6	2007	2008	2009	2010	2011 and beyond
64 and younger	4.60%	4.60%	4.60%	4.60%	4.60%	4.60%
65	9.50%	9.50%	8.71%	6.97%	6.60%	7.45%
66–74	16.11%	4.81%	3.88%	3.92%	3.81%	3.73%
75–79	9.61%	3.62%	2.95%	2.69%	2.51%	2.47%
80 and older	5.48%	3.10%	2.73%	2.51%	2.51%	2.47%

Table 3. Scenario analysis.

		Scenario A		Scenario B		Scenario C		Scenario D^†
		PPV23	PCV13	PPV23	PCV13	PPV23	PCV13	PPV23	PCV13
Vaccine effectiveness (serotype specific)	Against IPD, E and AR i.c.	74% [14]	74% ^‡	50% [14]	60% ^§	80% [14]	90% ^§	50% [14]	90% ^§
	Against IPD, E and AR i.s.	35% [15]	35% ^‡	1% [15]	1% ^‡	69% [15]	69% ^‡	1% [15]	69% ^‡
	Against NBPP, E and AR i.c.	39% [52]	39% ^‡	0% ^¶	0% ^‡	64% [18]	64% ^‡	0% ^¶	64%^† ^†
Disease-related costs		–		−20%		20%		−20%
Change in IPD incidence in adults over time	PCV13 not PCV7	Decrease		No change		Decrease		No change
	Not PCV13	Increase		No change		Increase		No change

^†Only for the comparison of PPV23 versus PCV13.

^‡Based on efficacy estimates for PPV23.

^§Assumptions in favor of PCV13.

^¶Assuming no efficacy against NBPP.

AR: At-risk adults; E: The elderly; i.c.: Immunocompetent; i.s.: Immunosuppressed; IPD: Invasive pneumococcal disease; NBPP: Non-bacteremic pneumococcal pneumonia; PCV: Pneumococcal conjugate vaccine; PPV: Pneumococcal polysaccharide vaccine.

Table 4. Waning function.

Year since the initial vaccination	Value (of initial effectiveness)
1	82%
2	78%
3	72%
4	64%
5	54%
6	43%
7	30%
8	15%
9 and more	0%

Table 5. Costs.

Parameter	Base case values	Ref.
Cost of vaccine (1 dose)	PPV23: £8.32 PCV13: £49.10	[56]
Administration	£6.92	[Sanofi Pasteur msd, Data On File], [57,60]
Pneumococcal pneumonia and hospitalized NBPP, per episode	£1787.42	[59,66]
Meningitis, per episode	£2573.26	[59,66]
Non-hospitalized NBPP, per episode	£220.65	[59,60,67]
PMS, per year	£3934.96	[58,60]

NBPP: Non-bacteremic pneumococcal pneumonia; PMS: Post-meningitis sequelae.

Figure 4. Total number of invasive pneumococcal disease cases.

Figure 5. Total budget and budget impact.

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