Elsevier

Vaccine

Volume 24, Issue 18, 1 May 2006, Pages 3984-3989
Vaccine

Late vaccination reinforcement during a measles epidemic in Niamey, Niger (2003–2004)

https://doi.org/10.1016/j.vaccine.2006.01.049Get rights and content

Abstract

Low measles vaccination coverage (VC) leads to recurrent epidemics in many African countries. We describe VC before and after late reinforcement of vaccination activities during a measles epidemic in Niamey, Niger (2003–2004) assessed by Lot Quality Assurance Sampling (LQAS). Neighborhoods of Niamey were grouped into 46 lots based on geographic proximity and population homogeneity. Before reinforcement activities, 96% of lots had a VC below 70%. After reinforcement, this proportion fell to 78%. During the intervention 50% of children who had no previous record of measles vaccination received their first dose (vaccination card or parental recall). Our results highlight the benefits and limitations of vaccine reinforcement activities performed late in the epidemic.

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

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