[Immunization coverage of children aged 0 to 5 years in Libreville (Gabon)]

The strategies recently implemented in Gabon have been effective in improving immunization coverage. These include, in particular, the integration of the Expanded Programme on Immunization (EPI) in primary health care centers, the integration of immunization outside of EPI, immunization by peripheral health centers according to pre-set advanced strategies, and awareness and catch-up campaigns. This descriptive, cross-sectional survey was conducted from 1 October 2007 through 30 January 2008, throughout public- and private-sector health care centers in the town of Libreville. In the public sector, where health care is free, the study took place at the largest health facility in the country, the Hospital Center of Libreville (HCL), at Estuary Mélen Hospital (on the outskirts of Libreville), at Nkembo Hospital, which houses the EPI offices, and the 5 Maternal and Child Health centers (MCH) where vaccine monitoring is done. Monitoring in the private sector covered only the three largest clinics, where vaccine monitoring is done, all of which agreed to participate. After obtaining informed consent from the parents or guardian accompanying the child, a semi-structured interview according to a standardised questionnaire was conducted to collect socioeconomic and demographic data, including age, sex, recruitment site, place of residence, number of siblings, parental origin, ethnicity of head of household, type of family (couple or single parent), mother's age, level of education, employment and socio-economic status, as determined by the head of household's monthly income (in three categories: 1) low income, at or below the minimum wage, set at 80 000 FCFA (120 euros); 2) average income, from more than 80 000 FCFA to 300 000 FCFA (458 euros); and 3) high income over 300 000 FCFA. After the interview, the child's vaccination booklet was carefully examined to identify the types of antigen, number of doses administered, age at vaccination, and the regularity of the monitoring. Parents were asked to explain the reasons for any delays in or absences of vaccinations. EPI vaccines administered to children aged 0 to 11 months include: BCG (Calmette-Guérin bacillus); DPT3 (3rd combination dose for Diphtheria-Tetanus-Pertussis); Hib3 (3rdd dose of Haemophilus influenza b); OPV3 (3rd dose of oral polio vaccine); IPV3 (3rd dose of injectable polio vaccine, often in combination); HEB3 (3rd dose of Hepatitis B); yellow fever vaccine; and measles vaccine. The non-EPV vaccines for children aged 12 to 59 months included: HiB4; DPT4; HEB4; IPV4; MMR (combined Measles-Mumps-Rubella); meningococcal vaccine A and C; Typhim Vi (typhoid polysaccharide vaccine); and Pneumo 23 (pneumococcal vaccine.)

The study included 1001 children: 533 boys (53.2%) and 468 girls (46.8%), for a sex ratio of 1.1. The mean age of the sample was 12.0 ± 13.1 months, distributed as follows: 64.5% aged 0 to 11 months; 20.1% aged 12 to 24 months; and 15.4% aged 25 to 59 months. In all, 175 children (17.5%) came from the private sector, and 826 children (82.5%) from the public sector. Both parents lived with 696 children (69.5%), while the remaining 305 children (30.5%) lived with their mother. The mothers' mean age was 26 years (min/max: 15/49 years); 61.3% had completed secondary education, 19.1% superior level, 10.6% primary level and 9.0% had no education at all. Almost 37% of mothers had some sort of paid employment. Household income was distributed as follows: low income for 18.6%, average income for 47.2%, and high income for 34.3% of the families interviewed. The average number of children under the age of 15 in a household was 3 (±2). Among children aged 0 to 11 months, the EPI antigens had the highest vaccination coverage rates, and these rates were higher in the private sector (more than 80% to 99% for some). Overall, the BCG scar was seen in 98.5% of all children; in the private sector 90.2% had received the third dose of the DTC/VPO-IPV vaccine, and in the public sector, 74.5%. The measles vaccination rate in the private sector was 82.5% compared with 64.4% in the public sector. The rates of coverage for antigens not included in the EPI varied from 50.8% to 74.2% in the private sector and from 6.2% to 32.5% in the public sector. The vaccine with the least coverage was the pneumococcal: only 3.2% and were vaccinated against this in the private sector and 0.8% in the public sector. The principal reasons for non-immunization were lack of financial resources (n = 283, 28.3%), in particular, for booster up vaccines and those recommended by the EPI, lack of information (n = 259, 25.9%), forgetfulness (n = 217, 21.7%), neglect (n = 113, 11.3%), sick child (n = 80, 8%), vaccine not available (n = 19, 1.9%), wrong information (n = 15, 1.5%), travel (n = 14, 1.4%), mother sick (n = 12, 1.2%) and lack of time (n = 18, 1.8%). Finally, the direct cost of good vaccination coverage for boosters was 42,245 FCFA (74 euros) in the public sector and 54,800 FCFA (84 euros) in the private sector.