Routine childhood immunization (RCI) in Pakistan is well below the recommended coverage of 90% with rates as low as 16% in certain regions (Pakistan DHS 2012-3). This has led to continued polio transmission, large measles outbreaks and thousands of deaths from vaccine-preventable diseases (Kazi.Bull WHO 2016). Mobile phone communication is widespread in developing countries and has proven a potential method of directly connecting pregnant women and mothers to health services (Kharbanda. Expert Review of Vaccine 2014). The investigators propose conducting a mixed methods proof of concept cluster randomized trial (CRT) to assess the effectiveness of different types of SMS messaging and automated calls to improve RCI and understand the perceptions and barriers that may affect SMS and automated call-based interventions at participants levels. the investigators will conduct the study at urban and rural sites in Pakistan. The investigators will examine an important public health question - do low cost, automated SMS, and automated messages improve RCI coverage in resource-constrained settings? Further, investigators will compare the effectiveness of reminder, educational and interactive text messages for improving RCI and will generate socio-cultural data regarding the impact of participants health beliefs that will be important for setting up the appropriate interventions in other LMICs.

SMS text messages have shown to be effective for mobile health or mHealth having a considerable impact on disease prevention efforts in developing countries. Mobile phone and SMS texting provide an excellent solution to challenges like travel and complex intercultural contact. SMS based interventions have been quite effective in different programs, particularly in treatment adherence, smoke cessation, health care appointment attendance, antenatal care attendance and compliance with immunization. In addition adding incentives to SMS messages have shown a positive association, however, there is a cost implication for scaling up this model at a country level. Given the mobile phone access and acceptability in the LMIC, there is great potential for SMS based intervention to improve Immunization coverage in LMIC setup.

One major reservation for SMS based interventions is the level of literacy. However, there has been mixed input related to the preference of phones calls as compared to text messages in populations of low literacy and resource-constrained settings. Mobile phone text messages in local languages, pictorial messages and in combination with a phone call can further reduce this gap.

Most of the studies evaluating the impact of text messages on vaccination have been conducted in the United States with a major focus on flu vaccine among children and teenagers. The participants covered in these studies are from low income background at an academic medical center and is quite different from resource constraint settings of LMICs due to poor immunization registries and electronic records. There is limited data from LMICs set up on the role of SMS based interventions for improvement of RI coverage and conventional one-way reminder text messages were used by most of the studies as the intervention. Overall very few investigators compared reminders, educational and interactive SMS messages related to childhood vaccination uptake. Although some of the investigators have shown some behavior change for improvement in vaccination coverage, more rigorous application of health behavior change model needs to be applied to understand the impact of reminder, educational and interactive messages on behavior change related to improvement in RI coverage. Very few studies have compared the effect of educational, reminders and interactive messages in improving uptake and on-time routine immunization.

In this study the investigators would like to examine an important public health question - do low cost, automated SMS messages and calls improve RI coverage among participants in resource-constrained settings? In this study, we would like to compare the effectiveness of reminder, educational and interactive text messages and phone calls for improving RI uptake in Pakistani participants.

Inclusion Criteria:

• The inclusion criteria includes being a child from the HDSS site, being less than 14 days of age with parent/guardian or at least one person in the household having a working mobile phone connection and parent/guardian providing consent to participate in the study.

Exclusion Criteria:

• The exclusion criteria includes a child from outside HDSS area or family plans to stay in the catchment area for less than 20 weeks