Sending postcard reminders increases vaccination rates among elderly

What was the challenge?

The Centers for Disease Control and Prevention identify adults over age 65 as higher-risk for vaccine preventable diseases and recommends vaccines for the influenza, tetanus, pneumonia, and shingles. The Louisiana Department of Health (LDH) identified increasing the number of vaccinated elderly as a priority, as well as interest in testing the impact of outreach efforts.

What was the program change?

LDH sent a postcard reminder on recommended vaccines to all elderly ages 65-70 in the Louisiana Immunization Information Registry. Reminder-based interventions have been shown to be an effective way to increase compliance with vaccine schedules by reducing rates of forgetfulness and complacency. Research shows that reminders may be particularly helpful in encouraging the elderly to vaccinate.

How did the evaluation work?

Individuals were randomly assigned to a month in which they received the postcard reminder, October, November, December, or January. In addition to month, individuals were block-randomized according to their vaccination history.

This study has three treatment arms based on when the postcard was sent: October, November, and December. Individuals randomized to receive the postcard reminder in January were considered the control group, as vaccinations rates were analyzed for the full sample excluding vaccinations post-January.


What was the impact?

The postcard reminder had a small but detectable effect among individuals who received the postcard in October.

Individuals in the control group received 8.58 percent of their four vaccinations during the study period. Individuals in the October group received 0.27 percent more vaccinations (an additional 563 vaccinations) than individuals in the control group.

The increase in vaccinations in October is detectable, while increases in November and December are not.

To verify the upload date of our Analysis Plan, click here.

Related Publication
Noule Chen, Pompa Debroy, Stacy Hall, and Quan Le. Postcards-increasing vaccination rates among elderly: U.S. Office of Evaluation Sciences and LDH Immunization Program. Louisiana Morbidity Report 30 no. 2 (April 2019): 3-7.





Project Type

Program Change and Evaluation


Health and Human Services




View Analysis Plan (PDF)

View Abstract (PDF)

View Intervention Pack (PDF) View Publication (PDF)