Vaccination coverage in colombia, opportunity and factors associated: Results from a national survey

To estimate the coverage of the Expanded Programme on Immunization among children ≤5 years old in Colombia, to evaluate the opportunity of vaccination, and to identify factors associated with low coverage. We conducted a cross-sectional survey in 80 municipalities of Colombia, with census block groups as primary sampling units, and blocks as secondary units. We identified all children in the targeted age group living in the sampled blocks, and asked their caregivers to provide children´s immunization record cards, when available. We also collected basic socio-demographic information. All procedures adhered to international guidelines on ethical conduct of research, and were approved by the IRB at the National University of Colombia, School of Medicine. Estimated coverage was good for vaccines scheduled during the first 15 months of life: BCG 93.2% (95%CI: 92–94.4), DTP/Hib/HepB 89.6% (87.8–91.5), MMR 92.5% (90.8–94.2), yellow fever 89.5% (87.1–91.8); but was lower among older children: DTP first booster dose 85.1% (83.4–86.7), second booster dose 63.7% (57.3–70.2); MMR booster dose 52.9% (46.4–59.4). Opportunity of vaccination showed poorer results: for instance, timely administration of DTP/Hib/HepB occurred in only 44.2% of the children evaluated (41.4–47.1), and MMR in 71.2% (68.9–73.4). Higher socioeconomic status, time living in the municipality, mother´s years of school completed, and affiliation to social security were associated with better vaccine coverage (p<0.001); children of internally displaced families, children pertaining to a minority, and those coming from families with greater number of siblings had lower coverage. Vaccination coverage in children <15 months meets the WHO goal of 90%, or is very close to it, though coverage in older children falls below that goal. Delayed immunization is a common problem in Colombia, which may result in reduced protection. There are few modifiable factors associated with low coverage, though the identification of vulnerable populations may help to improve the reach of immunization programs.