High coverage of vitamin A supplementation and measles vaccination during an integrated Maternal and Child Health Week in Sierra Leone.

BACKGROUND: In May 2012, the twice-yearly Maternal and Child Health Week (MCHW) integrated vitamin A supplementation (VAS) and supplementary measles vaccination to reach all children 6-59 months in Sierra Leone. Following the MCHW, a post event coverage survey was conducted to validate VAS coverage and assess adverse events following immunization. METHODS: Using the WHO Expanded Program on Immunization sampling methodology, 30 clusters were randomly selected using population proportionate to size sampling. Fourteen caregivers of children 6-59 months were interviewed per cluster for precision of ±5%. Responses were collected via mobile phones using EpiSurveyor. RESULTS: Overall VAS and measles coverage was 91.9% and 91.6%, respectively, with no significant differences by age group, sex, religion or occupation. Major reasons given for not receiving VAS and measles vaccination were not knowing about the MCHW or being out of the area. Significantly more mild adverse events (fever, pain at injection site) were reported via the post event coverage survey (29.1%) than MCHW (0.01%) (p<0.0001). CONCLUSION: The MCHW reached >90% of children in Sierra Leone with equitable coverage. Increased reporting of mild adverse events during the survey may be attributed to delayed onset after measles vaccination and/or direct inquiry from enumerators. Even mild adverse events following immunization requires strengthened reporting during and after vaccination campaigns.

Vaccination coverage survey versus administrative data in the assessment of mass yellow fever immunization in internally displaced persons--Liberia, 2004.

Yellow fever (YF) is a mosquito-borne vaccine-preventable disease with high mortality. In West Africa, low population immunity increases the risk of epidemic transmission. A cluster survey was conducted to determine the effectiveness of a mass immunization campaign using 17D YF vaccine in internally displaced person (IDP) camps following a reported outbreak of YF in Liberia in February 2004. Administrative data of vaccination coverage were reviewed. A cluster sample size was determined among 17,384 shelters using an 80% vaccination coverage threshold. A questionnaire eliciting demographic information, household size, and vaccination status was distributed to randomly selected IDPs. Data were analyzed to compare vaccination coverage rates of administrative versus survey data. Among 87,000 persons estimated living in IDP camps, administrative data recorded 49,395 (57%) YF vaccinated persons. A total of 237 IDPs were surveyed. Of survey respondents, 215 (91.9%, 95% CI 88.4-95.4) reported being vaccinated during the campaign and 196 (83.5%, 95% CI 78.6-88.5) possessed a valid campaign vaccination card. The median number of IDPs living in a shelter was 4 (range, 1-8) and 69,536 persons overall were estimated to be living in IDP camps. Coverage rates from a rapid survey exceeded 90% by self-report and 80% by evidence of a vaccination card, indicating that the YF immunization campaign was effective. Survey results suggested that administrative data overestimated the camp population by at least 20%. An emergency, mop-up vaccination campaign was avoided. Coverage surveys can be vital in the evaluation of emergency vaccination campaigns by influencing both imminent and future immunization strategies.