To pilot test a mobile phone SMS (Short Message Service) system that will provide periodical messaging texts to mothers or custodians of infants who come for their first dose vaccines within the first 3 months of life to improve timely immunization coverage, vaccine acceptance and ensure vaccine safety monitoring. The intervention will include a "cloud-based" information system alimented by mobile phone data entry at the health post nurse level, that links child vaccination status and is able to remind parents and nurses of the need for next vaccination appointment and provide a system for reporting of adverse events following immunization in the immediate post-vaccination period.

Significance: Vaccine coverage and acceptance in many municipal districts of Guatemala and other low- and middle-income countries are below the acceptable 80% reported at the national level for DPT3 (diphtheria, pertussis, tetanus) and measles vaccines. Despite the considerable effort to introduce new vaccines like Hib (Haemophilus influenzae type B) and rotavirus, in many countries like Guatemala infants do not get immunized on time. Completion of the recommended primary series does not reach beyond 70% of eligible infants by 12 months of age, placing them at risk of disease due to incomplete protection and missing the opportunity to get vaccinated appropriately. Reasons for not getting vaccinated on time include the lack of a system of reminders for the target population, missed opportunities to get vaccinated at the health services due to the lack of vaccine inventories and timely supply of vaccines (including the need for "group sessions for vaccinations" in order to secure the cold chain and vaccine availability).

In addition, monitoring of adverse events following immunization is lacking in most low and middle-income countries. Public acceptance for immunization is based not only on the effectiveness of the vaccine to reduce illness and death, but in the perception of vaccine safety at the population level. To maintain the confidence and acceptance in immunization programs, the reporting and proper response to events following immunization is critical. Allowing parents to notify possible adverse events following immunization provides them with direct access to the health care system to obtain a rapid response for their concerns, but also feedback about the safety of the vaccines and maintain vaccine trust and acceptance. Mobile phone reminders have been used in some populations in high-income countries to recall patients for influenza vaccinations, collect data on asthma dairies, and ensure adherence to antiretroviral therapy. In Guatemala, a country with an estimated population of 14 million inhabitants, there are at least 15 million mobile phones reported in use. At least 4 out of 5 families own and use a mobile phone, and a recent rapid needs assessment from the area of Quetzaltenango showed that at least 48% of mothers from very poor families own and use a mobile phone. The availability of this technology provides with an opportunity to use it as a method to collect information regarding vaccine coverage, use, supply and even monitoring of vaccine safety concerns.

Specific Aims:

1) To pilot test the SMS immunization system that allows immunization reminders to parents and health care workers in order to improve the vaccine timeliness completion rate and overall immunization coverage

Study: 320 infants younger than 3 months of age from municipal districts in Guatemala known to have vaccine coverage rates for DPT3 below 80% and who are coming to the health services for their first dose of vaccine will be recruited for the study. After obtaining consent for participation in the study, the parents will be provided with a mobile phone with SMS capability and instructed on its use. The health care worker will use her mobile device to enter the data on the child including date of birth, mother´s mobile phone number, date of vaccination and vaccines given, and these data will be uploaded into a remote database linked to the mobile phone system.

After the child has been vaccinated the mother or custodian will receive the following SMS notifications:

1. Within 3 days of vaccination an SMS will be send inquiring for any serious or medically relevant adverse events following immunization that the parent will like to report. The response will be uploaded automatically after the parent provides a reply, and will prompt a call from the health care worker if an AEFI (Adverse events following immunization) has been reported into the system.
2. One week before the next scheduled date for 2nd and 3rd dose of vaccines, the parents will automatically receive daily SMS message for 3 consecutive days, instructing them to visit the health care center to vaccinate their children. If the child fails to attend the immunization appointment, the nurse will receive an automatic message one week later reminding her/him to physically recall the child for immunization.

Section II. How will you test it? The intervention will be tested in Guatemala City an area known to have attained vaccine coverage for Pentavalent/DTP3 of only 78% for all its districts in the latest Maternal Infant Health Survey conducted in 2008-2009. The development of the remote data base system as well as the mobile phone base platform will be done in conjunction with local phone companies. Those funds will provide the investment for the development of the software platform, and for the mobile phones and airtime to be given to parents and health care workers.

Essential Data and Outcomes for Phase 1:

1. Rates of completion of primary immunization series in the intervention group including age at completion for 2nd and 3rd doses and rates of missed opportunities for vaccination
2. Satisfaction and feedback about intervention from mother at study completion

Inclusion Criteria:

• Infants 1-3 months of age coming for their 1 dose of primary vaccines

Exclusion Criteria:

• Received 1 dose of vaccines, excluding BCG
• No mobile phone with SMS or unable to use SMS at home
• Intent to move from the clinic area in the next 6 months

Infants under 12 months of age from Ministry of Health Clinics in Guatemala City

1 year

Breaches in confidentiality or inadvertent information releases were monitored.

Study was not powered to assess efficacy. SMS texts platform did not have a reporting feature, limiting our ability to confirm message reception. High vaccine visit completion rates made evaluation of an effect challenging.