Late vaccination reinforcement during a measles epidemic in Niamey, Niger (2003–2004)
Section snippets
Background
Measles is the leading cause of vaccine-preventable disease death worldwide causing 282,000 deaths in Africa in 2003 [1]. Despite a safe, effective and inexpensive vaccine, national childhood immunization program coverage has remained low in many African countries. As a result, countries with low coverage continue to face recurrent measles epidemics.
Measles is endemic in Niger with large epidemics occurring every 2 or 3 years. The Expanded Program on Immunization (EPI) was introduced in Niger
Methods
Niamey is divided into three administrative districts (Commune I, II, III) consisting of 108 neighborhoods with a total population estimated to be 769,500 (Central Office for Census, Niger, France). The 108 neighborhoods of Niamey were grouped into 46 areas, called lots, based on geographic proximity and population homogeneity (Mapping Department, Central Office for Census, Niger). The population of the lots ranged from 3780 to 43,680 residents. Of the 46 lots, 19 lots were in Commune I, 18
Results
The LQAS survey was conducted between 19 and 25 April 2004 (3 days after the end of reinforcement activities). Twenty survey teams of two persons each collected information on a total of 2990 children aged 6–59 months residing in the 46 lots.
Before reinforcing EPI activities, 96% (n = 44) of lots had a VC below 70% considering vaccination status based on vaccination cards. Results of the LQAS survey varied by Commune: in Commune II 89% (n = 16) of lots were considered to have insufficient VC, while
Discussion
The results of this survey confirm the low VC in Niamey prior to the 2003–2004 epidemic and identify areas of the city with inadequate VC. In this survey, 50% of children with no prior record of vaccination received their first dose during the reinforcement. The reinforcement activities also provided a second opportunity for previously vaccinated children.
This study highlights the benefits and limitations of reinforcement vaccination activities performed 23 weeks after cases are first reported.
Conclusion
One of the current objectives of the WHO strategic plan for measles is to reduce the number of measles deaths by half by 2005 (relative to 1999 estimates) through four strategies: achieve high-routine VC (>80%); provide a second opportunity for measles vaccination for all children; implement a strong surveillance system; and improve measles case management [8]. The results of this research point to the need for a clear and directed effort to achieve high VC in urban areas like Niamey if the WHO
Acknowledgements
This research work was supported by Médecins Sans Frontières and the World Health Organization. We thank the Ministry of Health of Niger for their support during the epidemic investigations. We also thank the MSF team in Niger for their committed work during this epidemic. In Niger, several individuals were key to the collection of the data used in this analysis: Dr Abdulaye Djibo (MSF), who was in charge of data collection during the epidemic; and Moussa Mallam Barke (epidemiologist at the
References (14)
Progress in reducing global measles deaths: 1999–2003
Wkly Epidemiol Rec
(2005)- et al.
Measles vaccine effectiveness in standard and early immunization strategies, Niger, 1995
Pediatr Infect Dis J
(1998) - et al.
Measles epidemic in the urban community of Niamey: transmission patterns, vaccine efficacy and immunization strategies, Niger, 1990–1991
Pediatr Infect Dis J
(1994) - World Health Organization. Department of Immunization Vaccines and Biologicals Vaccine Assessment and Monitoring Team...
- Dubray C. Epidémie de rougeole à Niamey. Accessible at:...
- Myatt M. SampleLQ—a sample size calculator for community-based triage surveys using lot quality assurance sampling....
- World Health Organization. Guidelines for epidemic preparedness and response to measles outbreaks, WHO/CDS/CSR/ISR/99....
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