Improving Childhood Immunization Completion in Rural Bayelsa State, Nigeria: A Pragmatic Cluster Randomized Trial of Mobile Phone Reminders and Home Visits
Background: Immunization is a critical public health intervention for preventing vaccine-preventable diseases (VPDs) and achieving herd immunity. However, suboptimal vaccination coverage remains a challenge, particularly in rural and underserved areas. Missed appointments due to forgetfulness and logistical barriers contribute significantly to low immunization rates. This study evaluates the impact of mobile phone (MP) reminders and home visits (HV) on childhood immunization completion rates in Bayelsa State, Nigeria. Aim: The study aimed to assess the effectiveness of MP reminders and HV outreach in improving vaccination coverage among children under two years of age. Methods: A pragmatic cluster randomized controlled trial was conducted in rural communities of Bayelsa State, Nigeria. A total of 384 participants were randomly assigned to three study arms: control (no intervention), MP reminders, and HV outreach (128 per arm). A multi-stage sampling technique was employed, and data were collected using a semi-structured WHO SAGE survey tool. Statistical analyses were performed using SPSS v25, with chi-square (χ2) tests used to compare categorical variables. Statistical significance was set at p ≤ 0.05, with effect sizes reported. Results: The study revealed significant differences in immunization completion rates across study groups: control (46.1%, 59/128), MP reminders (59.4%, 76/128), and HV outreach (63.3%, 81/128). Both interventions were effective in improving vaccination uptake, with a statistically significant difference (p = 0.015) and a moderate effect size (0.257). However, HV outreach demonstrated the highest completion rate, suggesting its greater effectiveness in overcoming access and engagement barriers. Conclusion: Integrating MP reminders and HV outreach into routine immunization programs can significantly improve childhood vaccination coverage. HV, in particular, addresses accessibility challenges and enhances community trust, making it a preferred strategy for increasing immunization rates. To optimize immunization coverage, policymakers should implement a hybrid approach, combining MP reminders with HV outreach, particularly in rural and underserved areas. Strengthening community-based health worker engagement and leveraging digital health innovations will further enhance vaccination efforts. Improved immunization coverage through these interventions reduces the risk of VPD outbreaks, enhances herd immunity, and contributes to achieving global vaccination targets. By addressing
References
[1]
Kakwi, J.D., Yakasai, K.M., Raimi, M.O. and Kakwi, J.D. (2024) Understanding the Dynamics of COVID-19 Vaccine Uptake in Plateau State, Nigeria: Analyzing Socioeconomic, Cultural, and Communication Influences. https://preprints.jmir.org/ojs/index.php/preprints/preprint/70702
[2]
Kakwi, J.D., Yakasai, K.M., Kakwi, J.D. and Raimi, M.O. (2024) Campaigning against Vaccine Hesitancy: Evaluating the Effectiveness of Health Communication on COVID-19 Vaccination Uptake in Plateau State, Nigeria. https://preprints.jmir.org/preprint/66755
[3]
Promise, V.I., Macauley, T., Alabere, I., Abdulraheem, I. and Raimi, M.O. (2024) Closing the Gap: Assessment of Vaccination Coverage among under Two Children in Bayelsa State, Nigeria. https://preprints.jmir.org/preprint/70671
[4]
Okechukwu, C.O., Ainu, M., Adias, T.C., Elemuwa, C.O., Rotifa, S.U., Ogbointuwei, C., et al. (2024) Evaluating the Impact of Rotavirus Vaccination on Childhood Diarrhea Incidence in Bayelsa State, Nigeria: Achievements, Challenges, and Future Directions. https://preprints.jmir.org/preprint/64822
[5]
Uchenna, G.E., Enato, E., Christopher, O.E., Tochukwu, D.E. and Morufu, O.R. (2024) Pentavalent Vaccine: How Safe Is It among Infants Accessing Immunization in Nigerian Health Facilities.
[6]
Raimi, M.O., Emeka, C.L., Ebikapaye, O., Angalabiri, C., Christopher, O. and Atoyebi, B. (2021) COVID-19 Decision Impacts: Vaccine Hesitancy, Its Barriers and Impact Studies: Taking Bayelsa State as an Example.
[7]
Raimi, M.O., Omidiji, A.O., Ebikapaye, O., Moses, T., Adeolu, T.A. and Makanjuola Bosede, C. (2019) Situational Analysis of National Immunization Programme in Nigeria. Journal of Immunology and Inflammation Diseases Therapy, 1, 1-6.
[8]
Raimi, O.M., Lucky, E.C., Okoyen, E., Clement, A., Ogbointuwei, C., et al. (2021) Making Better Informed, More Confident COVID-19 Decisions: Vaccine Hesitancy, Its Barriers and Impact Studies: Taking Bayelsa State as an Example. The International Journal of Vaccines and Immunization, 6, 126. https://sciforschenonline.org/journals/vaccines/IJVI126.php
[9]
Centers for Disease Control and Prevention (2011) Ten Great Public Health Achievements: United States, 2001-2010. Morbidity and Mortality Weekly Report, 60, 619-623.
[10]
World Health Organization (2021) Immunization Agenda 2030: A Global Strategy to Leave No One Behind. https://www.who.int
[11]
Oweibia, M., Elemuwa, U.G., Akpan, E., et al. (2024) Analyzing Nigeria’s Journey towards Sustainable Development Goals: A Comprehensive Review from Inception to Present. F1000Research, 13, Article No. 984.
[12]
Mordecai, O., et al. (2024) Analyzing Nigeria’s Journey towards Sustainable Development Goals: A Comprehensive Review from Inception to Present. Qeios, 1-34.
[13]
World Health Organization (2024) DNA Vaccines. https://www.who.int
[14]
Andersson, N., Cockcroft, A., Ansari, N.M., Omer, K., Baloch, M., Ho Foster, A., et al. (2009) Evidence-Based Discussion Increases Childhood Vaccination Uptake: A Randomised Cluster Controlled Trial of Knowledge Translation in Pakistan. BMC International Health and Human Rights, 9, S8. https://doi.org/10.1186/1472-698x-9-s1-s8
[15]
Nigeria Demographic Health Survey (2018) Demographic Health Survey. https://www.dhsprogram.com
Haji, A., Lowther, S., Ngan’ga, Z., Gura, Z., Tabu, C., Sandhu, H., et al. (2016) Reducing Routine Vaccination Dropout Rates: Evaluating Two Interventions in Three Kenyan Districts, 2014. BMC Public Health, 16, Article No. 152. https://doi.org/10.1186/s12889-016-2823-5
[18]
Kagucia, E.W., Ochieng, B., Were, J., Hayford, K., Obor, D., O’Brien, K.L., et al. (2021) Impact of Mobile Phone Delivered Reminders and Unconditional Incentives on Measles-Containing Vaccine Timeliness and Coverage: A Randomised Controlled Trial in Western Kenya. BMJ Global Health, 6, e003357. https://doi.org/10.1136/bmjgh-2020-003357
[19]
World Health Organization/United Nation Children Emergency Fund (2023) Progress and Challenges with Achieving Universal Immunization Coverage: 2018 WHO/UNICEF Estimates of National Immunization Coverage, Geneva. https://www.who.int/teams/immunization-vaccines-and-biologicals/immunization-analysis-and-insights/global-monitoring/immunization-coverage/who-unicef-estimates-of-national-immunization-coverage
[20]
Ibrahim, M.L., Sawyerr, H.O., Opasola, O.A., Adiama, Y.B. and Raimi, M.O. (2025) Bridging Knowledge and Practice Gaps in Lassa Fever Prevention: Awareness, Attitudes, and Infection Control Measures Among Healthcare Workers and Residents in Edo, Ondo, and Kwara States. https://preprints.jmir.org/preprint/75233
[21]
Elemuwa, C.O., Raimi, M.O., Ainu, M., Adias, T.C., Ufuoma, R.S., Elemuwa, U.G., et al. (2024) Conquering Mpox: A Comprehensive Public Health Strategy for Addressing Mpox and Poxvirus Infections in Nigeria-Understanding Global Trends, Transmission Dynamics, and Effective Prevention and Control Measures in Nigeria. https://preprints.jmir.org/preprint/67534
[22]
Abaya, S.T., Ogoina, D., Stow, J., Abaye, B.B., Emeka, C. and Raimi, M.O. (2024) Beyond the Epidemic: Effective Public Health Strategies in Response to Nigeria’s First Lassa Fever Outbreak in a Non-Endemic Region. https://preprints.jmir.org/preprint/65539
[23]
Elemuwa, C.O., Ainu, M., Adias, T.C., et al. (2024) Transforming Primary Healthcare in Nigeria: Enhancing Universal Health Coverage through Strong and Sustainable Primary Healthcare Laboratories. Qeios.
[24]
Morufu, O.R., Aziba-anyam, G.R. and Teddy, C.A. (2021) Evidence-Based Environmental and Public Health Practices to Respond to the COVID-19 Crisis, 07 May 2021. https://europepmc.org/article/PPRID/PPR335534
[25]
Elemuwa, C.O., Ainu, M., Adias, T.C., Abisoye Sunday, O., Stella Ufuoma, R., Elemuwa, U.G., et al. (2024) Boosting Community Engagement: Leveraging the Ward Health System Approach for Enhanced HPV Vaccination Acceptance in Nigeria. F1000Research, 13, Article No. 1392. https://doi.org/10.12688/f1000research.153919.1
[26]
Raimi, M.O. and Raimi, A.G. (2020) The Toughest Triage in Decision Impacts: Re-thinking Scientific Evidence for Environmental and Human Health Action in the Times of Concomitant Global Crises. CPQ Medicine, 11, 1-5.
[27]
Raimi, M.O., Moses, T., Okoyen, E., Sawyerr, H.O., Joseph, B.O. and Oyinlola, B.O. (2020) A Beacon for Dark Times: Rethinking Scientific Evidence for Environmental and Public Health Action in the Coronavirus Diseases 2019 Era. Medical and Research Microbiology, 1.
[28]
Samson, T.K., Ogunlaran, O.M. and Raimi, O.M. (2020) A Predictive Model for Confirmed Cases of COVID-19 in Nigeria. European Journal of Applied Sciences, 8, 1-10.
[29]
Akwataghibe, N.N., Ogunsola, E.A., Broerse, J.E.W., Popoola, O.A., Agbo, A.I. and Dieleman, M.A. (2019) Exploring Factors Influencing Immunization Utilization in Nigeria—A Mixed Methods Study. Frontiers in Public Health, 7, Article No. 392. https://doi.org/10.3389/fpubh.2019.00392
[30]
Ahmad, R.A., Hayat, M.I.G., Sahalu, B.J., Muhammad, N.S., Halima, M.A., Au-walu, M. and Abdulmaleek, M.A. (2020) Perception of Health Workers on Use of Immunization Mobile Application at Primary Health Care Facilities in Kano State, Nigeria. Journal of Medicine and Biomedical Research, 19, 43-49.
[31]
Sarker, A.R., Akram, R., Ali, N., Chowdhury, Z.I. and Sultana, M. (2019) Coverage and Determinants of Full Immunization: Vaccination Coverage among Senegalese Children. Medicina, 55, Article No. 480. https://doi.org/10.3390/medicina55080480
[32]
Bangure, D., Chirundu, D., Gombe, N., Marufu, T., Mandozana, G., Tshimanga, M., et al. (2015) Effectiveness of Short Message Services Reminder on Childhood Immunization Programme in Kadoma, Zimbabwe—A Randomized Controlled Trial, 2013. BMC Public Health, 15, Article No. 137. https://doi.org/10.1186/s12889-015-1470-6
[33]
Akinrinade, O.T., Ajayi, I.O., Fatiregun, A.A., Isere, E.E. and Yusuf, B.O. (2018) Ownership of Mobile Phones and Willingness to Receive Childhood Immunization Reminder Messages among Caregivers of Infants in Ondo State, South-Western Nigeria. South African Journal of Child Health, 12, 111-116.
[34]
Siddiqi, D.A., Ali, R.F., Munir, M., Shah, M.T., Khan, A.J. and Chandir, S. (2020) Effect of Vaccine Reminder and Tracker Bracelets on Routine Childhood Immunization Coverage and Timeliness in Urban Pakistan (2017-18): A Randomized Controlled Trial. BMC Public Health, 20, Article No. 1086. https://doi.org/10.1186/s12889-020-09088-4
[35]
Ekhaguere, O.A., Oluwafemi, R.O., Badejoko, B., Oyeneyin, L.O., Butali, A., Lowenthal, E.D., et al. (2019) Automated Phone Call and Text Reminders for Childhood Immunisations (PRIMM): A Randomised Controlled Trial in Nigeria. BMJ Global Health, 4, e001232. https://doi.org/10.1136/bmjgh-2018-001232
[36]
Domek, G.J., Contreras-Roldan, I.L., O’Leary, S.T., Bull, S., Furniss, A., Kempe, A., et al. (2016) SMS Text Message Reminders to Improve Infant Vaccination Coverage in Guatemala: A Pilot Randomized Controlled Trial. Vaccine, 34, 2437-2443. https://doi.org/10.1016/j.vaccine.2016.03.065
[37]
Domek, G.J., Contreras-Roldan, I.L., Bull, S., O’Leary, S.T., Bolaños Ventura, G.A., Bronsert, M., et al. (2019) Text Message Reminders to Improve Infant Immunization in Guatemala: A Randomized Clinical Trial. Vaccine, 37, 6192-6200. https://doi.org/10.1016/j.vaccine.2019.08.046
[38]
Jacobson Vann, J.C., Jacobson, R.M., Coyne-Beasley, T., Asafu-Adjei, J.K. and Szilagyi, P.G. (2018) Patient Reminder and Recall Interventions to Improve Immunization Rates. Cochrane Database of Systematic Reviews, 2018, CD003941. https://doi.org/10.1002/14651858.cd003941.pub3
[39]
Isaac, M.R., Chartier, M., Brownell, M., Chateau, D., Nickel, N.C., Martens, P., et al. (2015) Can Opportunities Be Enhanced for Vaccinating Children in Home Visiting Programs? A Population-Based Cohort Study. BMC Public Health, 15, Article No. 620. https://doi.org/10.1186/s12889-015-1926-8
[40]
Promise, V.I., Alabere, I., Abdulraheem, I. and Raimi, M.O. (2025) The Effect of Mobile Phone and Home Visit on Childhood Vaccination Uptake in Rural Communities of Bayelsa State Nigeria. A Pragmatic Cluster Randomized Control Trial. https://preprints.jmir.org/preprint/75332
[41]
Babbo, D., Raimi, M.O., Samson, T.K., Adesina, A.D., Adaka, O.A. and Jatau, S.S. (2025) Understanding HPV Vaccine Awareness and Knowledge through Sociodemographic Profiling and Multivariable Predictive Modelling in Port Harcourt Local Government Area, Nigeria. https://preprints.jmir.org/preprint/89196
[42]
Kakwi, J.D., Yakasai, K.M., Kakwi, J.D. and Raimi, M.O. (2025) Promotion over Pixels: A Mixed-Methods Analysis of Vaccine Communication Strategies in Plateau State, Nigeria. BMJ Open, 15, e094029. https://doi.org/10.1136/bmjopen-2024-094029
[43]
Raimi, M.O., Geraldine, E.U. and Jatau, S.S. (2025) Bridging Gaps in Childhood Immunization Timeliness: Global Evidence from JRF Data with a Spotlight on Nigeria. The ACS-FUO Conference of the Faculty of Science, Federal University Otuoke, Bayelsa State on the Theme: Harnessing Green Chemistry & Artificial Intelligence for Sustainable Development, Otuoke, 4-7 November 2025, 97.
[44]
Raimi, M.O., Adias, T.C. and Elemuwa, C.O. (2025) Leveraging Artificial Intelligence to Develop a Nigerian Vaccine Impact Vulnerability Index (NVIVI) for Sustainable Public Health and Environmental Safety. The ACS-FUO Conference of the Faculty of Science, Federal University Otuoke, Bayelsa State on the theme: Harnessing Green Chemistry & Artificial Intelligence for Sustainable Development, Otuoke, 4-7 November 2025, 33.
[45]
Elemuwa, U.G., Elemuwa, C.O. and Raimi M.O. (2025) Leveraging Artificial Intelligence for Proactive Pharmacovigilance: A National Security Imperative for HPV Vaccine Deployment in Nigeria. The ACS-FUO Conference of the Faculty of Science, Federal University Otuoke, Bayelsa State on the Theme: Harnessing Green Chemistry & Artificial Intelligence for Sustainable Development, Otuoke, 4-7 November 2025, 123.
[46]
Raimi, A.G. and Raimi, M.O. (2025) Leveraging Digital Platforms for Community-Driven Public Health Surveillance in the Niger Delta: A Feasibility Study from Bayelsa State, Nigeria. The ACS-FUO Conference of the Faculty of Science, Federal University Otuoke, Bayelsa State on the Theme: Harnessing Green Chemistry & Artificial Intelligence for Sustainable Development, Otuoke, 4-7 November, 2025, 124
[47]
Michael-Olomu, O., et al. (2025) Strengthening Green Health System Sustainability through Enrollee-Centered Policy Reform: Insights from the National Health Insurance Scheme (NHIS) in Nigeria. The ACS-FUO Conference of the Faculty of Science, Federal University Otuoke, Bayelsa State on the theme: Harnessing Green Chemistry & Artificial Intelligence for Sustainable Development, Otuoke, 4-7 November, 2025, 137.
[48]
Adiama, Y.B., Raimi, M.O. and Usiobaifo, A.H. (2025) Echoes of Outbreaks Past: Rethinking Public Health Preparedness in Sub-Saharan Africa in the Age of Emerging Pandemics. The 3rd Ku8+ International Conference, Kwara State University, Malete with the Theme “Innovation and Sustainability of Higher Education in a Changing World”, Otuoke, 6-8 August 2025, 26.
[49]
Opasola, O.A. and Raimi, M.O. (2025) From Crisis to Catalyst: Lever-Aging Public Health Emergencies to Redesign Urban Health Policy in Nigerian Megacities. The 3rd Ku8+ International Conference, Kwara State University, Malete with the Theme “Innovation and Sustainability of Higher Education in a Changing World”, Otuoke, 6-8 August 2025, 28.
[50]
Hofstetter, A.M., DuRivage, N., Vargas, C.Y., Camargo, S., Vawdrey, D.K., Fisher, A., et al. (2015) Text Message Reminders for Timely Routine MMR Vaccination: A Randomized Controlled Trial. Vaccine, 33, 5741-5746. https://doi.org/10.1016/j.vaccine.2015.09.042
[51]
Gibson, D.G., Ochieng, B., Kagucia, E.W., Were, J., Hayford, K., Moulton, L.H., et al. (2017) Mobile Phone-Delivered Reminders and Incentives to Improve Childhood Immunisation Coverage and Timeliness in Kenya (M-SIMU): A Cluster Randomised Controlled Trial. The Lancet Global Health, 5, e428-e438. https://doi.org/10.1016/s2214-109x(17)30072-4
[52]
Kagucia, E.W., Ochieng, B., Were, J., Hayford, K., Obor, D., O’Brien, K.L., et al. (2021) Impact of Mobile Phone Delivered Reminders and Unconditional Incentives on Measles-Containing Vaccine Timeliness and Coverage: A Randomised Controlled Trial in Western Kenya. BMJ Global Health, 6, e003357. https://doi.org/10.1136/bmjgh-2020-003357
[53]
Kazi, A.M., Ali, M., Zubair, K., Kalimuddin, H., Kazi, A.N., Iqbal, S.P., et al. (2018) Effect of Mobile Phone Text Message Reminders on Routine Immunization Uptake in Pakistan: Randomized Controlled Trial. JMIR Public Health and Surveillance, 4, e20. https://doi.org/10.2196/publichealth.7026
[54]
Raimi, M.O. (2025) Peer Review Report For: Zero-Dose Childhood Immunization in Conflict-Affected Productive Safety Net Program Districts of Ethiopia: A Comparative Cross-Sectional Study.
[55]
Raimi, M.O. (2025) Peer Review Report For: Zero-Dose Childhood Immunization in Conflict-Affected PSNP Districts of Ethiopia: A Comparative Cross-Sectional Study.
[56]
Raimi, M.O. (2025) Peer Review Report for: Mapping Community Vulnerability to Reduced Vaccine Impact in Uganda and Kenya: A Spatial Data-Driven Approach. NIHR Open Research, 5, Article No. 24.
[57]
Raimi, M.O. (2025) Peer Review Report For: Mapping Community Vulnerability to Reduced Vaccine Impact in Uganda and Kenya: A Spatial Data-Driven Approach. NIHR Open Research, 2025, 5:24.
[58]
Raimi, M.O. (2025) Peer Review Report for: Development of a Health Impact Assessment Implementation Model: Enhancing Intersectoral Approaches in Tackling Health Inequalities—A Mixed Methods Study Protocol. HRB Open Research, 7, 14. https://hrbopenresearch.org/articles/7-14/v3#referee-response-45418
[59]
Oginifolunnia, O.C., Elemuwa, C.O., Adias, T.C., Raimi, M.O. and Angalabiri, C. (2025) Bridging the Gaps: Unveiling Weaknesses in Disease Surveillance during Mass Immunization Campaigns in Nigeria. https://preprints.jmir.org/preprint/80148
[60]
Landoh, D.E., Ouro-kavalah, F., Yaya, I., Kahn, A., Wasswa, P., Lacle, A., et al. (2016) Predictors of Incomplete Immunization Coverage among One to Five Years Old Children in Togo. BMC Public Health, 16, Article No. 968. https://doi.org/10.1186/s12889-016-3625-5
[61]
Raimi, O.M., Sunday, O.A., Mcfubara, K.G., Adias, T.C., Raimi, G.A., Daniel, A.A., Izah, S.C., Okoyen, E., Ogbointuwei, C., Clement, A., Godspower, A. and Funmilayo, A.A. (2022) Perspective Chapter: Applying Innovative Research as a Tool to Advance Immunization Coverage in Bayelsa State, Nigeria. In: Raimi, M.O., Sunday, O.A., Sawyerr, H.O. and Adias, T.C., Eds., Emerging Issues in Environmental Epidemiology and Its Reflection [Working Title], IntechOpen, 1-31.
[62]
Morufu, O.R., Aziba-anyam, G.R. and Teddy, C.A. (2021) “Silent Pandemic”: Evidence-Based Environmental and Public Health Practices to Respond to the Covid-19 Crisis. IntechOpen. https://www.intechopen.com/online-first/silent-pandemic-evidence-based-environmental-and-public-health-practices-to-respond-to-the-covid-19-Published
[63]
Abdulraheem, A.F., Ononokpono, D.N. and Raimi, M.O. (2025) Breaking Barriers to Safe Motherhood: How Social, Cultural, and Geographic Inequalities Shape Skilled Birth Attendance in Nigeria. Sociology International Journal, 9, 188-200.
[64]
Abdulraheem, A.F., Ononokpono, D.N. and Raimi, M.O. (2025) Breaking Barriers: How Socio-Demographic, Cultural, and Geographic Factors Shape Skilled Birth Attendance in Nigeria—A Call for Equity and Empowerment. https://preprints.jmir.org/preprint/78050
[65]
Abdulraheem, A.F., Raimi, M.O. and Ononokpono, D.N. (2025) Who Delivers Safely? The Hidden Role of Transport and Education in Nigeria’s Maternal Health Crisis. https://preprints.jmir.org/preprint/79460
[66]
Sawyerr, H.O. and Raimi, M.O. (2025) Surveillance in the Shadows: Reinventing Community-Based Disease Monitoring Systems in Rural Nigeria. The 3rd Ku8+ International Conference, Kwara State University, Malete with the Theme “Innovation and Sustainability of Higher Education in a Changing World”, Malete, 6-8 August 2025, 33.
[67]
Teddy, C.A., Christopher, O.E. and Morufu, O.R. (2025) Community Engagement and Social Innovation for Environmental Justice in Sub-Saharan Africa. The 1st International Conference of the Faculty of Science, Federal University Otuoke, Bayelsa State on the Theme: Revolutionizing a Sustainable Tomorrow: Harnessing Science, Innovation and Community Power to Drive Circular Economy Solutions, Climate Resilience, and a Thriving Green Economy, Otuoke, 4-7 March 2025, 75.
