"To date, no study has evaluated the effect of a radio-only campaign on infant vaccination coverage, timeliness, and related morbidity in a low-income country. We implemented the "10+10+30" radio campaign involving broadcasting a weekly 10-minute radio drama series on vaccination, followed by a 10-minute discussion by community health workers, and then a 30-minute listener phone-in segment in Jimma Zone, Ethiopia for three months. To assess the impact of 10+10+30, which was aired on a community radio station, we recruited mothers of infants up to 5 weeks old in intervention district clusters that were inside the radio station's reception range (n = 328 dyads) and control district clusters that were outside of the range (n = 332 dyads). Intention-to-treat and per-protocol analyses, adjusted for pre-intervention differences between the districts, were conducted to examine the co-primary outcome of Penta-3 vaccination coverage and timeliness as well as those of other vaccines and outcomes related to infant morbidity. Both intention-to-treat and per-protocol analyses revealed higher vaccine coverage and more timely vaccine administration in the intervention district relative to the control district, with infants in the intervention district being 39% more likely to receive a Penta 3 vaccination. In addition, adjusted regression analyses of maternal retrospective reports over a two-week period revealed 80% less infant diarrhoea, 40% less fever and 58% less cough in the intervention district relative to the control district. This study provides compelling initial evidence that a radio drama integrated with discussion and phone-in components may improve infant vaccination coverage and timeliness and may reduce infant morbidity." (Abstract)