[An immunisation coverage survey in the Kouilou area of Congo-Brazzaville]

An internal review of the expanded program of immunisation undertaken on the basis of daily data collected over the past five years from 1993 to 1997 in the region of Kouilou revealed a weak coverage level for all the antigens, associated with a strong dropout rate. In August 1999, a vaccination coverage survey was carried out on three strata of the Kouilou area in order to determine the proportion of children vaccinated by antigens. The method used is that of sampling clusters. It concerned 663 children aged between 12 and 23 months chosen among 30 urban, 30 periurban and 30 rural clusters. The BCG scar was found in 82.8% children while 71.8% had received the third dose of VIP-OPV. Some 62.6% were immunised against measles. Within the region, the coverage rates varied from 87.9 to 57.1% for BCG; 80.3 to 41% for DTP-OPV3 and 7.3 to 41% for measles. A considerable variation of dropout rates was observed at area level: 8.9 to 14.7% for DTP-OPV3 and 9 to 11% for measles immunisation. The average interval observed between VPT-OVP 1 and VPT-OVP 2 was, respectively, 6.1 and 6.2 weeks in urban areas against 6.4 and 6.9 weeks in periurban areas. On the other hand in rural zones, the interval was of 7.6 weeks between VPT-OVP and DPT-OPV2 and of 10.1 weeks between DPT-OVP2 and DPT-OVP3. The median interval was of 5 weeks for the different DPT-OVP doses in all the strata. The vaccination card was found in 90% of cases in urban areas, 96% in urban zones and 55% in rural zones. The coverage level attained per antigen is satisfactory, but remains to be strengthened. Dropout rates are high enough and they should be corrected. Follow-up actions should focus on raising a strong awareness for vaccination in rural areas. Besides, the vaccination of target populations living in remote areas by way of mobile and outreach strategies could improve the immunisation coverage rate.