Measles outbreak in Northern Central African Republic 3 years after the last national immunization campaign.

Vianney Tricou,Marilou Pagonendji,Ionela Gouandjika-Vasilache,Rock Ouambita Mabo,Casimir Manengu,Jeff Mutombo

doi:10.1186/1471-2334-13-103

Abstract

BackgroundDespite huge efforts to promote widespread vaccination, measles remains an important cause of morbidity and mortality worldwide, especially in African children. In March 2011, an abnormally high number of cases were reported from the Ouham Prefecture, Central African Republic to the national measles case-based surveillance system. In response, reactive vaccination activities were implemented. The aims of this study were to investigate this outbreak and describe the response.MethodsMeasles cases were defined according to WHO recommendations. In the first weeks of the outbreak, blood samples were collected and sent to the Institut Pasteur in Bangui for laboratory confirmation by detection of IgM antibodies against measles virus. In addition, a portion of viral RNA was amplified from 5 IgM positive patient samples and the amplicons were sequenced for phylogenetic analysis.ResultsBetween March and September 2011, 723 clinical cases originated from the Ouham Prefecture, including 2 deaths, were reported. Amongst 59 blood samples collected, 49 were positive for the detection of IgM. A high number of self-declared vaccinated subjects (31%) were found amongst the cases. Most of the cases were under 5 years. The causative virus was found to belong to genotype B3.1. In response, 2 sub-national supplementary immunization activities were quickly conducted and limited this outbreak to mainly 2 sub-prefectures.ConclusionsThis outbreak was the largest epidemic of measles in CAR since 2002. Its occurrence, 3 years after the last national immunization campaign, highlights the necessity to pursue efforts and improve and extend immunization programs in order to reach measles elimination goal in Africa.

Highlights

Despite huge efforts to promote widespread vaccination, measles remains an important cause of morbidity and mortality worldwide, especially in African children
We reviewed information about all the cases originated from the Ouham Prefecture in northern Central African Republic (CAR) reported to the national measles case-based surveillance system between March and September 2011
No IgM antibody was found in 7 blood samples, and the corresponding cases were considered as discarded measles cases (2 were diagnosed as rubella)

Summary

Introduction

Despite huge efforts to promote widespread vaccination, measles remains an important cause of morbidity and mortality worldwide, especially in African children. In March 2011, an abnormally high number of cases were reported from the Ouham Prefecture, Central African Republic to the national measles case-based surveillance system. Measles is a highly contagious viral disease, which affects the respiratory system, mostly in children. Huge efforts have been recent resurgence of measles in Europe despite substantial progress made towards measles elimination but where the insufficient vaccination coverage has allowed for silent accumulation of susceptible individuals [5]. The Central African Republic (CAR), one of the poorest countries of the world, is affected by political instability and internal conflicts for more than a decade. In northern CAR, close to 200,000 persons have been displaced between 2005 and 2008 and micro-displacement continues to this date due to constant insecurity

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