RANDOMIZED CONTROLLED TRIAL OF TEXT MESSAGE TO INCREASE PNEUMOCOCCAL VACCINATION IN ADULTS IN CHILE.

Summary

The goal of this randomized controlled trial is to learn if text message reminders sent through WhatsApp increase pneumococcal vaccination coverage in adults turning 65 years old in Chile. The main questions it aims to answer are:

Do text message reminders increase the proportion of adults aged 65 years who receive the pneumococcal vaccine compared to usual care? Do text message reminders increase pneumococcal vaccination coverage within the first 7 days after the message is sent? Is there an association between socioeconomic factors and pneumococcal vaccination coverage in adults aged 65 years in Chile?

Researchers will compare adults who receive a text message reminder to adults who receive no reminder (usual care) to see if the reminders increase vaccination uptake.

Participants will:

Be randomly assigned to receive a WhatsApp text message reminder about the pneumococcal vaccine or to receive no reminder Receive a second reminder on day 14 if they have not yet been vaccinated (intervention group only) Be followed for 6 weeks, with vaccination status checked at days 7, 21, and 42 from the start of the intervention

Conditions

• Pneumococcal Infections
• Immunization Programs
• Vaccination Coverage
• Text Messaging (Intervention)
• Reminder Systems
• Health Promotion
• Aged 65 Years or Older

Interventions

BEHAVIORAL

WhatsApp text message reminder for pneumococcal vaccination

A text message reminder sent via WhatsApp on day 0 of the intervention by the Ministry of Health of Chile, through the official National Immunization Program contactability platform EMILIA (Rayén Salud). The message includes: (1) an official presentation identifying the Ministry of Health of Chile as the sender; (2) a reminder that the recipient is eligible for free pneumococcal vaccination upon turning 65 years of age; (3) confirmation that the 23-valent pneumococcal polysaccharide vaccine (PPV23) is guaranteed and available at no cost through the National Immunization Program; and (4) the name, address, and operating hours of vaccination centers in the participant's municipality of residence. A second reminder message with identical content will be sent on day 14 to participants in the intervention arm who have not yet received the vaccine. The message was developed by the National Immunization Program and the Ministry of Health Communications Unit, based on the Yale-UNICEF Vaccine M

Sponsors & Collaborators

• Ministry of Health, Chile

  collaborator OTHER_GOV

• Pablo Tomás Valenzuela García

  lead OTHER

Principal Investigators

• Pablo Valenzuela García, MD, MSc · Pontifical Catholic University of Chile. National Immunization Program, Ministry of Health, Chile.

• Ignacio Castro Aguirre, MD; MPH · National Immunization Program, Ministry of Health, Chile.

Study Design

Allocation

RANDOMIZED

Purpose

PREVENTION

Masking

NONE

Model

PARALLEL

Eligibility

Min Age

64 Years

Max Age

65 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2026-07-15

Primary Completion

2026-09-01

Completion

2026-10-01

Countries

• Chile

Study Locations