Table 1.

Characteristics of 7 included studies.

Authors (year); country			Targeted vaccine and population		Study type, time frame, and perspective		Interventions		Base-case and sensitivity analyses
Web-based decision aid
	Tubeuf et al (2014) [30]; United Kingdom	MMRa vaccine; 3- to 12-month-old individuals		Trial-based analysis; 17 months; National Health Service and societal perspective		(1) MMR web-based decision aid and usual practice, (2) MMR leaflet and usual practice, and (3) usual practice		Base-case analysis: web-based decision aid with usual practice—cost-saving and higher vaccination rate Sensitivity analysis: probability of web-based decision aid to be cost-effective was 72%-88% at WTPb threshold of £0-£100 (US $0-US $124.35)
Television campaign
	Kim and Yoo (2015) [24]; United States	Influenza vaccination; Medicare individuals aged 65 years and older		Decision tree model; 1 year; societal perspective		(1) Television (nationwide) campaign and (2) no television campaign		Base-case analysis: television campaign—US $17.79 cost per additional case vaccinated Sensitivity analysis: television campaign remained cost-effective if vaccination coverage rate increased with television campaign (by at least 0.5%) for non-Hispanic White or broadcasting cost <US $14,870,000; mean ICERc US $23.54 (95% CI US $14.21-US $39.37) in 10,000 Monte-Carlo simulations
SMS text messaging
	Kawakatsu et al (2020) [29]; Nigeria	Childhood vaccination; younger than 12 months		Trial-based analysis; 14 weeks; government’s perspective		(1) SMS text messaging reminder (2) no intervention		Base-case analysis: US $7.9 cost per additional return case Sensitivity analysis: two scenario analyses (excluded appointments and used the inverse-probability weighted method) found effectiveness results to be robust
Recall and reminder by telephone/computer
	Lieu et al (1997) [25]; United States	MMR vaccine; 20-month-old individuals		Decision tree model; 4 months; payer’s perspective		(1) Computer-generated recall letters and (2) no intervention		Base-case analysis: US $4.04 cost per additional child immunized Sensitivity analysis: influential factors were effectiveness of recall letters and the baseline population coverage rate Scenario analyses: US $2.14 per additional child immunized using telephone autodialer compared with no intervention
	Lieu et al (1998) [26]; United States	Childhood immunization; 20-month-old individuals		Decision tree model; 4 months; payer’s perspective		(1) Automated telephone message alone, (2) letter alone, (3) letter followed by an automated telephone message, and (4) no intervention		Base-case analysis (vs no intervention) cost per additional child immunized: letter followed by automated telephone message: US $7.00 Automated telephone message alone: US $9.80; letter alone: US $10.50 Sensitivity analysis: cost per child immunized in automated telephone message alone decreased from US $9.8 to US $2.20 when lower cost per telephone message was applied
	Franzini et al (2000) [28]; United States	Childhood immunization; <1 year of age		Trial-based analysis; 1 year; societal perspective		(1) Computer-autodialer reminder, (2) manual postcard mail, and (3) no intervention		Base-case analysis (vs no intervention): cost per return visit—computer autodialer: US $3.48; manual mail: US $9.52. Cost per return immunization: computer autodialer: US $4.06; manual mail: US $12.82 Sensitivity analyses: influential factors were effectiveness of computer-autodialer in return visit and immunization and start-up costs of computer-autodialer system
	Spencer et al (2020) [27]; United States	HPVd vaccine; 11-17 years old		Dynamic simulation model, 50 years; government’s perspective		(1) Reminder and recall (phone call, email, text, or mailing), (2) QIe visit, and (3) school-located vaccination		Base-case analysis (vs no intervention): QI visits: US $1538/QALYf reminder and recall: US $13,183/QALY; school-located vaccination: US $14,871/QALY; (WTP=US $50,000/QALY) Sensitivity analysis: Probability of being cost-effective was 83% for school-located vaccination, 12% for reminder and recall, and 5% for QI visit at a WTP of US $50,000 per QALY gained

^aMMR: measles-mumps-rubella.

^bWTP: willingness-to-pay.

^cICER: incremental cost-effectiveness ratios.

^dHPV: human papillomavirus.

^eQI: quality improvement.

^fQALY: quality-adjusted life years.