Understanding the main barriers to immunization in Colombia to better tailor communication strategies.

Background: The Expanded Program on Immunization (EPI) in Colombia has made great advances since its inception in 1979; however, by 2010 vaccination coverage rates had been declining. In 2010, the EPI commissioned a nationwide study on practices on immunization, attitudes and knowledge, perceived service quality, and barriers to childhood immunization in order to tailor EPI communication strategies.

Methods: Colombia's 32 geographical departments were divided into 10 regions.