New Study Shows that SMS Reminders and Incentives Improve Immunization Coverage and Timeliness in Kenya

A new study published in The Lancet Global Health found that in a setting with high baseline immunization coverage levels, SMS reminders coupled with small monetary incentives significantly improved immunization coverage and timeliness in rural western Kenya. Given that global immunization coverage levels have stagnated around 85%, the use of text message reminders and incentives might be one option to reach the remaining 15% — which are typically the hard-to-reach populations.

Dustin Gibson, PhD working with Danny Feikin, MD, Kate O’Brien, MD and other colleagues at IVAC, led the study with key partners from the Kenya Medical Research Institute (KEMRI) and CDC Public Health Collaboration. In the study, 152 villages were randomized to one of four arms: (1) control; (2) SMS reminders only; (3) SMS reminders plus a 75 Kenya Shilling (KES) incentive; and (4) SMS reminders plus 200 KES (85 KES = USD$1).  Participants in the intervention groups received SMS reminders before scheduled pentavalent and measles immunization visits. Participants in incentive groups additionally received small amounts of money if their child received timely immunization (immunization within 2 weeks of the due date). Children were followed-up to age 12 months where the proportion of children who were fully immunized (receiving BCG, three doses of polio vaccine, three doses of pentavalent vaccine, and measles vaccine) and immunization timeliness (receiving vaccines within two weeks of their Expanded Programme on Immunization scheduled date) were compared across study arms.

The investigators found an 8% increase in full immunization between children of caregivers who received SMS reminders plus a 200 KES (90%) versus those in the control arm (82%). The authors also looked at timely immunization; which is often understudied but very important from a herd immunity perspective.  Timely measles immunization significantly improved by 9% in children of caregivers who only received text message reminders – with a 21% increase in those who received SMS reminders and a 200 KES incentive.  Gains in measles coverage and timeliness are particularly important  because measles is a highly infectious virus; outbreaks can occur in populations when even  5% of children are immunologically susceptible.  Equally important, the authors’ findings suggest that interventions did not exacerbate existing inequities in coverage; the text messages and incentives reached many of the traditionally disadvantaged populations who would benefit most. “Making vaccines accessible is sometimes not enough,” explains Dr. Gibson. “Even with high access, people do not receive all vaccines. This research looked at ways to generate demand for immunizations in rural Kenyan caregivers and we may have found one way to increase immunization coverage and timeliness.”

Amidst the Decade of Vaccines and the backdrop of global access to mobile phones, global health experts are searching for ways to meet the Global Vaccine Action Plan targets and reach all children with life-saving vaccines. This study provides rigorous scientific evidence for one potential solution to vaccinate the hardest to reach children ­­­ – using mobile technology and small financial incentives to enhance demand for immunization and increase full, timely vaccine coverage.

Read the full study here. A commentary written by Abdul Momim Kazi (Aga Khan University) is also available.