Modelling the population-level benefits and cost-effectiveness of cell-based quadrivalent influenza vaccine for children and adolescents aged 6 months to 17 years in the US

Figures & data

Table 1. Key model parameters.

Item	Values	Reference
Proportion of individuals assumed protected prior to vaccination	27%	[26,27]
Probability of symptomatic infection^a	0.313–0.910	[28]
Probability of hospitalization^a	0.0006–0.0421	[28]
Probability of death^a	0.00001–0.01170	[28]
Vaccine effectiveness QIVe^b	31–48%	[29]
rVE QIVc to QIVe children	8.1%	[28]
rVE QIVc to QIVe adults	11.4%	[28]
Vaccine coverage^c	34–73%	[30]
Cost of GP consultation^d	$56.88–$1147.49	[28]
Cost of hospitalization per episode^d	$8513.45–$74,709.10	[28]
Loss of productivity costs^d	$14.84–106.34	[28]
Vaccine cost^e	$19.92–$63.00	[31]
QALY lost per hospitalization^d	0.013–0.076	[28]
QALY lost per non-fatal ILI^d	0.005–0.007	[28]
Discounting rate	3%	–

GP, general practitioner; ILI, influenza-like illness; QALY, quality-adjusted life year; QIVc, cell-based quadrivalent influenza vaccine; QIVe, egg-based quadrivalent influenza vaccine; rVE, relative vaccine effectiveness.

^aFor further details of estimates by age see Supplementary Table S1.

^bFor further details of estimates by age see Supplementary Table S2.

^cFor further details of estimates by age see Supplementary Table S3.

^dFor further details of estimates by age see Supplementary Table S4.

^eFor further details of estimates by age see Supplementary Table S5.

Table 2. Estimated number of symptomatic influenza cases, GP visits, hospital visits, and deaths at a population level in low and high incidence influenza seasons with the use of QIVe or QIVc in children aged 6 months to 17 years.

	Symptomatic cases	GP visits	Hospital visits	Deaths
High incidence
QIVe	41,536,030	17,359,448	566,533	80,063
QIVc	39,879,759	16,711,185	549,845	77,937
Absolute difference	−1,656,271	−648,263	−16,688	−2,126
Relative difference	4%	4%	3%	3%
Low incidence
QIVe	4,377,497	1,755,718	48,824	6,432
QIVc	1,521,113	611,731	17,157	2,269
Absolute difference	−2,856,384	−1,143,987	−31,667	−4,163
Relative difference	65%	65%	65%	65%

GP, general practitioner; QIVc, cell-based quadrivalent influenza vaccine; QIVe, egg-based quadrivalent influenza vaccine.

Estimates were based on a total eligible US population size of 326 million.

Table 3. Estimated costs of GP visits, hospital visits, loss of productivity, and vaccination in low and high incidence influenza seasons with the use of QIVe or QIVc in children aged 6 months to 17 years. Costs are stated in USD.

	GP cost	Hospitalization cost	Loss of productivity cost	Vaccine cost	Total cost
High incidence
QIVe	$8,058,853,440	$18,028,597,298	$5,828,536,703	$5,738,957,442	$37,654,944,883
QIVc	$7,837,196,815	$17,562,347,553	$5,612,681,970	$6,174,054,040	$37,186,280,378
Absolute difference	-$221,656,625	-$466,249,745	-$215,854,733	$435,096,598	-$468,664,505
Low incidence
QIVe	$721,393,770	$1,480,183,662	$577,037,180	$5,738,957,442	$8,517,572,053
QIVc	$254,287,099	$522,347,058	$200,956,706	$6,174,054,040	$7,151,644,903
Absolute difference	-$467,106,671	-$957,836,604	-$376,080,474	$435,096,598	-$1,365,927,150

GP, general practitioner; QIVc, cell-based quadrivalent influenza vaccine; QIVe, egg-based quadrivalent influenza vaccine.

Table 4. Difference in total quality-adjusted life years (QALY) lost and incremental cost-effectiveness ratio (ICER) of QIVc versus QIVe from the payer and societal perspectives, in a low or high incidence influenza season.

Perspective	Total costs	Difference in total QALY lost	ICER
High incidence
Payer	-$252,809,772	−31,213	Dominant (-$8,100)
Societal	-$468,096,505	−31,213	Dominant (-$15,015)
Low incidence
Payer	-$989,846,477	−60,256	Dominant (-$16,427)
Societal	-$1,365,927,150	−60,256	Dominant (-$22,669)

ICER, incremental cost-effectiveness ratio; QALY, quality-adjusted life years; QIVc, cell-based quadrivalent influenza vaccine; QIVe, egg-based quadrivalent influenza vaccine.

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