Switching from trivalent to quadrivalent inactivated influenza vaccines in Uruguay: a cost-effectiveness analysis

Figures & data

Figure 1. Structure of the cost-effectiveness model.

Table 1. Input values used in the model and, where applicable, ranges used in the sensitivity analyses

Input	Value	DSA range	ICER		PSA distribution	Source
			Lower	Higher
Discount rate	3%	[0–6%]	14689.84	16627.39	Beta
		Aspects related to the vaccine
B strain distribution:^a  2013  2014  2015  2016  2017  2018  2019	38.8% 23.4% 36.6% 32.1% 38.5% 19.0% 10.7%	±20%			Beta	FluNet Network^Citation25
Match level^b	50%	[20–80%]	9510.03	41,564.84	Beta	Based on Reed 2012^Citation34
Vaccine efficacy against A  ≤4  5–19 high-risk  20–49 high-risk  50–64 high-risk  ≥65	0.59 0.61 0.61 0.61 0.58	[.41, .74] [.47, .70] [.48, .70] [.48, .70] [.38, .72]	15,921.00	15,921.00		Ranges are the 95% CI reported in Clements et al.(2014)^Citation26
Vaccine efficacy against matched B  ≤4  5–19 high-risk  20–49 high-risk  50–64 high-risk  ≥65	0.66 0.77 0.77 0.73 0.69	[.12, .94] [.17, .94] [.18, .94] [.18, .96] [.16; .99]				Ranges are the 95% CI reported in Clements et al. (2014)^Citation26
Vaccine efficacy against mismatched B  ≤4  5–19 high-risk  20–49 high-risk  50–64 high-risk  ≥65	0.44 0.52 0.52 0.49 0.47	NA^c
Cross-protection	67%	[54%–81%]	11,066.67	28,317.82		Ranges were calculated based on Clements et al. (2014)^Citation26
Vaccination coverage:  ≤4  5–19 high-risk  20–49 high-risk  50–64 high-risk  ≥65	23.0% 10.2% 10.2% 10.2% 29.3%	±20%	15,921.00	15,921.00	Beta	Ministry of Health, Uruguay^Citation27
		Medical visits and direct costs
Influenza-attributable  GP consultation rates	Specific by age and season (see Suppl. Table S4)	±20%	17,808.75	14,360.16		Based on Molinari et al. (2007)^Citation28
Influenza-attributable hospitalization rates			15,956.45	15,885.54
Influenza-attributable mortality			17,792.84	14,405.50
Number of non-consulting cases per consulting case  ≤4  5–19 high-risk  20–49 high-risk  50–64 high-risk  ≥65	0.46 0.58 0.60 0.60 0.39	±20%	16,721.89	15,193.31	Beta (applied on the probability of consultation per case)	Based on Molinari et al. (2007)^Citation28
TIV price	US$2.65	+/- 20%	19,559.88	12,282.11		PAHO Revolving Fund, Vaccines Price 2019^Citation37
QIV price	US$5.14	+/- 20%	8862.93	22979.06		PAHO Revolving Fund, Vaccines Price 2019^Citation37
Cost of physician visit	US$82.05	+/- 20%	16115.48	15726.51	Log Normal	CINVE Consultora de Salud^Citation36
Cost of hospitalization	US$499.650	+/- 20%	15956.45	15885.54	Log Normal	CINVE Consultora de Salud^Citation36
Prescribed drug cost—GP visits and OTC		+/- 20%	15921.00	15921.00	Log Normal	Uruguay Pharmacy Center^Citation38
≤4	US$1.34
Other age groups	US$2.68
		Indirect costs
Workdays lost		+/- 20%	15921.00	15921.00	Log Normal	Aiko et al. (2000)^Citation39
Quality of life
Utility norms		NA
<4	0.9720
5–19 high-risk	0.8213
20–49 high-risk	0.7962
50–59 high-risk	0.7929
≥60	0.9300
QALY losses due to influenza		+/- 20%			Beta	Sander et al. (2010)^Citation47
≤4	0.0146
5–19 high-risk	0.0146
20–49 high-risk	0.0173
50–64 high-risk	0.0173
≥65	0.0293

^aB strains as a percentage of all reported cases.

^bPercentage match between the B subtype in the TIV vaccine and the dominant serotype during a season.

^cVaccine efficacy against mismatched B is calculated from efficacy against matched B and degree of cross-protection. As both of these were included in the sensitivity analysis, there was no need to include vaccine efficacy against mismatched B in the sensitivity analysis.

Details on the calculations for the parameters used in the PSA distribution are included in the supplemental material.

DSA, deterministic sensitivity analysis; GP, general practitioner; NA, not applicable; OTC, over-the-counter; PAHO, Pan American Health Organization; PSA, probabilistic sensitivity analysis; QALY, quality-adjusted life-year; QIV, quadrivalent influenza vaccine; TIV, trivalent influenza vaccine.

Table 2. Health outcomes during an average influenza season (base case), number avoided with QIV vs TIV, and life-years and QALYs gained

	Total influenza cases	GP consultations	Hospitalizations	Deaths	Workdays lost
Total number
With TIV	106,851	70,972	1,605	246	56,754
With QIV	106,107	70,467	1,590	243	56,452
Number avoided with QIV vs TIV						Life-years gained	QALYs gained
Age group (years)
≤4	304	208	4	0	0	0	5
5–19 high-risk	112	71	0	0	42	0	2
20–49 high-risk	60	37	0	0	96	0	1
50–64 high-risk	36	23	1	0	51	1	1
≥65	232	167	10	3	113	23	28
Total^a	744	505	15	3	303	24	37

^aTotals may differ by 1 from the sum of the components due to rounding of results to whole numbers.

GP, general practitioner; QALY, quality-adjusted life-year; QIV, quadrivalent influenza vaccine; TIV, trivalent influenza vaccine.

Table 3. Additional vaccination cost and total incremental cost for switching from TIV to QIV (base case)

Age (years)	Additional vaccination cost (USD)	Total incremental cost: Payor perspective (USD)	Total incremental cost: societal perspective (USD)
≤4	$130,802	$111,336	$111,206
5–19 high-risk	$46,994	$40,933	$40,700
20–49 high-risk	$113,389	$110,110	$107,454
50–59 high-risk	$72,855	$70,584	$69,169
≥60	$365,054	$346,025	$345,138
Total	$729,095	$678,989	$673,667

QIV, quadrivalent influenza vaccine; TIV, trivalent influenza vaccine.

Table 4. Costs saved by switching from TIV to QIV for the targeted population in Uruguay during an average influenza season and ICERs (base case).

Age group (years)	Physician consultations	Hospitalizations	Prescribed drugs	OTC drugs	Productivity losses due to illness	Productivity losses due to death	ICER (cost per QALY)*
							Payor perspective	Societal perspective
≤4	$17,044	$2,144	$278	$129	NA	NA	$23,461	$23,434
5–19 high-risk	$5,809	$62	$190	$110	$124	$0	$24,320	$24,181
20–49 high-risk	$3,054	$125	$100	$60	$2,587	$10	$97,256	$94,909
50–64 high-risk	$1,860	$350	$61	$36	$1,302	$77	$56,368	$55,238
≥65	$13,702	$4,879	$448	$174	$493	$220	$12,291	$12,259
Total	$41,470	$7,560	$1,076	$509	$4,505	$307	$18,368	$18,224

ICER, incremental cost-effectiveness ratio; NA, not applicable; OTC, over-the-counter; QALY, quality-adjusted life-year.

*All costs are shown as USD.

Figure 2. Deterministic sensitivity analysis (societal perspective).

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