Abdul Momin Kazi, MBBS, MPH
Murtaza Ali, MS
Khurram Zubair, MS
Hussain Kalimuddin, MSc
Abdul Nafey Kazi, MBBS
Saleem Perwaiz Iqbal, MBBS, MSc
Jean-Paul Collet, MD, PhD
Syed Asad Ali, MBBS, MPH
Publication Date
March 7, 2018

Aga Khan University (A.M. Kazi, M. Ali, Zubair, Kalimuddin, A.N. Kazi, S.A. Ali, Iqbal); University of British Columbia (A.M. Kazi, Collet)

"Automated simple one-way SMS reminders in local languages might be feasible for improving routine vaccination coverage."

Improved routine immunisation (RI) coverage is recommended as the priority public health strategy to decrease vaccine-preventable diseases and eradicate polio in Pakistan and worldwide. The objective of this study was to ascertain whether customised, automated, one-way text messaging (short message service, or SMS) reminders delivered to caregivers via mobile phones when a child is due for an RI visit can improve vaccination uptake and timelines in Pakistan.

With the reemergence of polio in Nigeria, improvement in polio vaccine uptake as part of RI is important in eliminating polio and sustaining eradication in Pakistan and worldwide. Unfortunately, the immunisation coverage in Pakistan is estimated to be 59%, with rates as low as 16% in the Baluchistan province. Despite all the Expanded Program of Immunization (EPI) scheduled vaccines being free of cost, the coverage rate in Pakistan is well under 90%, as recommended for RI programmes in low- and middle-income countries (LMICs). Research shows that a major reason for poor coverage is the lack of awareness among parents and caregivers regarding the need for immunisation and the importance of completing the entire series of vaccines. There is a need for enhancement in the leverage between care seeker and the health care provider to improve vaccine uptake and complete all doses according to the schedule.

Given mobile phone access and acceptability in Pakistan, this study sought to explore the potential for SMS-based interventions to improve immunisation coverage. A randomised controlled trial (RCT) was conducted in an urban squatter settlement area of Karachi, Pakistan. Infants of fewer than 2 weeks of age with at least one family member who had a valid mobile phone connection and was comfortable receiving and reading SMS text messages were included. Participants were randomised to: a) the intervention group (standard care, which was one-time verbal counseling at the time of initial visit/study enrollment), plus four one-way SMS reminders, according to the language preference), or b) control group (standard care only). The primary outcome was to compare the proportion of children immunised up to date at 18 weeks of age. The schedule of vaccines given at 6, 10, and 14 weeks includes DPT-Hep-B-Hib vaccine (i.e., diphtheria, pertussis, and tetanus; hepatitis B; and Haemophilus influenza type b) and oral poliovirus vaccine (OPV). Data were analysed using chi-square tests of independence and tested for both per protocol (PP) and intention-to-treat (ITT) analyses.

Out of those approached, 84.3% (300/356) of the participants were eligible for enrollment, and 94.1% (318/338) of the participants had a working mobile phone. Only children in the PP analyses, who received an SMS reminder for vaccine uptake at 6 weeks visit, showed a statistically significant difference (96.0%, 86/90 vs. 86.4%, 102/118; P=.03). The immunisation coverage was consistently higher in the intervention group, according to ITT analyses at the 6 weeks scheduled visit (76.0% vs. 71.3%, P=.36). The 10 weeks scheduled visit (58.7% vs. 52.7%, P=.30) and the 14 weeks scheduled visit (31.3% vs. 26.0%, P=.31), however, were not statistically significant.

Reflecting on these findings, the researchers point to the large drop in vaccination rate from 6 to 10 and 14 weeks in the study. It shows that families are not opposed to the vaccine at 6 weeks (76% coverage) and that something happens after 6 weeks that makes the child's vaccine a second priority for the family. When discussing informally the reasons with few families, the researchers learned that some of the reasons reported were as follows: (1) the change in mother's status at 6 weeks (need to resume normal work activities); (2) poor experience with the first vaccine, perceived as painful for the child and/or responsible for fever and other adverse effects; (3) forgot child's due date for the next vaccination visit, or child's EPI card is misplaced; (4) not permitted by family members to have her child immunised; (5) difficulties in reaching the EPI centres at a convenient time; and (6) low trust regarding vaccines provided through EPI and government health care providers. "Incorporating these reasons to develop new SMS messages, including educational or proactive messages, might bring about the behavior change and strategies to decrease the drop in follow-up visits during the infancy period."

They also note that the vaccination coverage at 14 weeks in both the intervention and control arms was even lower than the national estimates, indicating the importance of additional interventions or support for improvement in vaccination uptake.

Looking beyond this study, the researchers explain that, although the major focus to date has been on reminder messages, the impact of educational or provoking messages for vaccination improvement might also improve vaccination coverage and should be evaluated in future studies in LMIC settings. In addition, they say, the impact of two-way SMS-based models using text messages compared with one-way SMS needs to be assessed for RI programmes. Adding incentives to SMS text messages has shown to have a positive association; however, there might be cost implications for scaling up this model at the programme level in LMICs. Furthermore, automated calls could be a good alternative for low-literate populations, although the cost could be a major hindrance as well.

On the topic of literacy, they continue by pointing to previous studies that have advocated that level of literacy might have a direct impact on the efficacy of SMS messages for improvement in immunisation coverage. In the present study, only one-third of the parents and person having the mobile phone in the house had no formal education; however, this does not rule out their capacity to reply to simple text messages. Although SMS text messages have the limitation of 160 characters and even fewer if translated into other characters, these limitations might help in making the messages simple and brief, especially for low-literacy level populations.

Regarding language issues, the researchers state that more than two-thirds of the study's participants opted for Pakistan's national language of Urdu; the majority of the remaining ones chose Roman Urdu (Urdu written with English alphabets), despite participants belonging to different ethnic groups with Urdu not being their mother tongue. This signifies the importance of SMS content according to the language preference.

In conclusion: "Whether SMS reminders alone alter parental attitudes and behavior needs to be evaluated by better-powered studies, comparing the different types and content of text messages in LMICs settings. In addition, information on perceptions, barriers, and text content according to the local settings that may affect SMS-based interventions should be assessed as well."


JMIR Public Health Surveillance 2018;4(1):e20. DOI: 10.2196/publichealth.7026. PMID: 29514773. Image credit: Pixabay; Copyright: rbalouria; URL:; License: Public Domain (CC0).