Cost-effectiveness of SMS appointment reminders in increasing vaccination uptake in Lagos, Nigeria: A multi-centered randomized controlled trial q Yoshito Kawakatsu a,1,⇑ , Adefunke Oyeniyi Adesina b,1 , Nobuhiro Kadoi c,1 , Hirotsugu Aiga d a Department of Global Health, University of Washington, USA b Lagos State Ministry of Health, Lagos, Nigeria c Project for Strengthening Pro-poor Community Health Services in Lagos State, Nigeria d School of Tropical Medicine and Global Health, Nagasaki University, Nagasaki, Japan article info Article history: Received 7 June 2020 Received in revised form 25 July 2020 Accepted 31 July 2020 Available online xxxx Keywords: Child Vaccination Antenatal care Family planning SMS Cost Effectiveness Nigeria abstract Objective: It is expected that mHealth largely contribute to increasing the coverages of key maternal and child health services. This study aims to estimate the cost-effectiveness of the SMS text reminders in cli- ents’ return visits to the health facilities for child vaccinations (incl. vitamin A supplementations), ante- natal care (ANC) and family planning (FP), in urban communities of Lagos, Nigeria. Methods: A multi-centered randomized control trial was conducted at 33 primary health centers (PHCs) in Lagos, Nigeria. All the clients having visited any of the 33 PHCs for child vaccinations, ANC and FP were randomly assigned either to intervention group or to control group. The participants in the intervention group were sent an SMS text reminder two days before their appointments. Those not having showed up on the appointment dates received an additional SMS text reminder seven days after original appointment dates as defaulter tracing. The primary outcome was whether a client made return visit to PHCs for the upcoming appointments. Results: Of 12,779 appointments for 9,368 clients during the period of 1st April to 30th June 2019, 12,175 were included in the analysis. The return rate for child vaccinations in the intervention group was signif- icantly higher (p < 0.001) by 4.8%  6.0% than that in the control group, consistently across all the five different timings (on time as scheduled, and by 7 days, 14 days, 30 days, and 3 months after appointment dates). No significant difference between the two groups was detected in the increase in return rates for ANC and FP services. The incremental recurrent cost was estimated at 7.90 US Dollars per return case. Conclusion: SMS text reminders led to a significant increase in the number of return visits for child vac- cinations, Lagos, Nigeria, while no significant increase in return visits was confirmed for ANC and FP appointments. Ó 2020 Elsevier Ltd. All rights reserved. 1. Background The world made remarkable progress in reducing maternal mortality ratio and under-five mortality rate by 44% and 53% respectively, between 1990 and 2015 [1,2]. Nonetheless, in 2015, more than 300 thousand women died globally, and nearly 6 million children died before reaching their fifth birthday [2]. Antenatal care (ANC) during pregnancy, family planning (FP), and child vaccinations are recognized as the effective public health interventions for reducing maternal and child morbidities and mortalities [3–7]. In order to further reduce the numbers of mater- nal and child deaths, innovative approaches are highly expected for increasing the coverages of key maternal and child health services through enhancing compliance with service scheduling and reme- dies among service users. Information and communication technology development has been rapidly surging into the healthcare sector not only in devel- oped world but also in developing world due to globally growing mobile networks, e.g. mobile health (mHealth). Numerous applica- tions have been developed and tested for adequate and timely uti- lizations for health services [8]. Among others, short messaging service (SMS) is being often employed as the possibly effective reminder means in low-middle income countries, too [9–11].A https://doi.org/10.1016/j.vaccine.2020.07.075 0264-410X/Ó 2020 Elsevier Ltd. All rights reserved. q Trial Registration: ISRCTN13178993 ⇑ Corresponding author at: 1959 NE Pacific Street, Seattle, WA 98195, USA. E-mail address: yoshitok@uw.edu (Y. Kawakatsu). 1 These authors contributed equally to this work. Vaccine xxx (xxxx) xxx Contents lists available at ScienceDirect Vaccine journal homepage: www.elsevier.com/locate/vaccine Please cite this article as: Y. Kawakatsu, A. Oyeniyi Adesina, N. Kadoi et al., Cost-effectiveness of SMS appointment reminders in increasing vaccination uptake in Lagos, Nigeria: A multi-centered randomized controlled trial, Vaccine, https://doi.org/10.1016/j.vaccine.2020.07.075