This study will take place at health centres and their affiliated schools and community immunization centers overseen by the Kampala Capital City Authority (KCCA) as well as at the Makerere/Mulago/Columbia Adolescent Health Clinic, also in Kampala. While text messages can be used in populations with low literacy, families can opt to receive automated phone call reminders instead. The investigators will pilot assess the impact of vaccine reminders on human papillomavirus (HPV) vaccination. Caregivers of preteens/adolescents will be randomized and stratified by site, language and HPV vaccine dose needed (initiation vs. completion). As this is a feasibility trial, the investigators expect to measure effect size but not necessarily achieve statistical significance.

Cervical cancer is the leading female cancer in Uganda. Many women are diagnosed with late-stage disease, and 80% of women die within 5 years of diagnosis, making primary prevention critical. HPV is the principal cause of cervical cancer, making vaccination the single most important primary preventive measure. The national HPV vaccination program in Uganda began in November 2015 and focuses solely on preteen/adolescent girls. Two strategies have been adopted for the multi-dose series: 1) school-based and 2) community-based. However, in Kampala, only 29% of girls receive both needed doses. Reasons for undervaccination include school absenteeism on special vaccination days for those receiving vaccination as part of a school program, failing to remember to come to a health facility for a needed dose for those being vaccinated in the community, and lack of knowledge regarding HPV and the vaccines including vaccine misperceptions. While research regarding the use of text message vaccine reminders is strong in the U.S., their use has not yet been demonstrated in a preteen/adolescent population in Sub-Saharan Africa and other low and middle income countries (LMICs). According to the World Bank, currently 89.9% of urban households in Uganda have a cell phone.

Inclusion Criteria:

• Be a parenting adult of an adolescent girl aged 10-14 years
• Reside in Kampala and/or the surrounding districts
• Speak English or Luganda
• Have a cell phone with text messaging capability
• Must have ability to consent

Exclusion Criteria:

• Parenting adult speaks other language than English or Luganda only
• Parenting adult already enrolled in the study for another child
• Participation in pretesting activities

6 months