Search

Abstract Background In November 2009, Sierra Leone conducted a preventive yellow fever (YF) vaccination campaign targeting individuals aged nine months and older in six health districts. The campaign was integrated with a measles follow-up campaign throughout the country targeting children aged 9–59 months. For both campaigns, the operational objective was to reach 95% of the target population. During the campaign, we used clustered lot quality assurance sampling (C-LQAS) to identify areas of low coverage to recommend timely mop-up actions. Methods We divided the country in 20 non-overlapping lots. Twelve lots were targeted by both vaccinations, while eight only by measles. In each lot, five clusters of ten eligible individuals were selected for each vaccine. The upper threshold (UT) was set at 90% and the lower threshold (LT) at 75%. A lot was rejected for low vaccination coverage if more than 7 unvaccinated individuals (not presenting vaccination card) were found. After the campaign, we plotted the C-LQAS results against the post-campaign coverage estimations to assess if early interventions were successful enough to increase coverage in the lots that were at the level of rejection before the end of the campaign. Results During the last two days of campaign, based on card-confirmed vaccination status, five lots out of 20 (25.0%) failed for having low measles vaccination coverage and three lots out of 12 (25.0%) for low YF coverage. In one district, estimated post-campaign vaccination coverage for both vaccines was still not significantly above the minimum acceptable level (LT = 75%) even after vaccination mop-up activities. Conclusion C-LQAS during the vaccination campaign was informative to identify areas requiring mop-up activities to reach the coverage target prior to leaving the region. The only district where mop-up activities seemed to be unsuccessful might have had logistical difficulties that should be further investigated and resolved.

Abstract Background The Global Immunization Vision and Strategy (GIVS) (2006-2015) aims to reach and sustain high levels of vaccine coverage, provide immunization services to age groups beyond infancy and to those currently not reached, and to ensure that immunization activities are linked with other health interventions and contribute to the overall development of the health sector. Objective To examine mid-term progress (through 2010) of the immunization coverage goal of the GIVS for 194 countries or territories with special attention to data from 68 countries which account for more than 95% of all maternal and child deaths. Methods We present national immunization coverage estimates for the third dose of diphtheria and tetanus toxoid with pertussis (DTP3) vaccine and the first dose of measles containing vaccine (MCV) during 2000, 2005 and 2010 and report the average annual relative percent change during 2000-2005 and 2005-2010. Data are taken from the WHO and UNICEF estimates of national immunization coverage, which refer to immunizations given during routine immunization services to children less than 12 months of age where immunization services are recorded. Results Globally DTP3 coverage increased from 74% during 2000 to 85% during 2010, and MCV coverage increased from 72% during 2000 to 85% during 2010. A total of 149 countries attained or were on track to achieve the 90% coverage goal for DTP3 (147 countries for MCV coverage). DTP3 coverage ≥ 90% was sustained between 2005 and 2010 by 99 countries (98 countries for MCV). Among 68 priority countries, 28 countries were identified as having made either insufficient or no progress towards reaching the GIVS goal of 90% coverage by 2015 for DTP3 or MCV. DTP3 and MCV coverage remained < 70% during 2010 for 16 and 21 priority countries, respectively. Conclusion Progress towards GIVS goals highlights improvements in routine immunization coverage, yet it is troubling to observe priority countries with little or no progress during the past five years. These results highlight that further efforts are needed to achieve and maintain the global immunization coverage goals.