PROGRESS TOWARD MEASLES PRE ELIMINATION — AFRICAN REGION, 2011–2012

Monday, 7th of April 2014

[source]Weekly Epidemiological Record (WER)[|source]

In 2008 the 46 member states of the WHO African Region (AFR) adopted a measles pre-elimination goal to be reached by the end of 2012. To attain this regional goal, the following strategies were to be used:

1. Attain >98% reduction in estimated regional measles mortality compared with 2000;
2. Achieve annual measles incidence of <5 reported cases nationally per million population;
3. Attain >90% national coverage of first dose of measles-containing vaccine (MCV1) and >80% MCV1 coverage in all districts; and
4. Reach >95% MCV coverage in all districts by supplementary immunization activities (SIAs)

In this report, the authors provide an update of previous reports and describe progress towards the measles pre-elimination goal during 2011–2012 period. Full text findings, discussions and recommendations are accessible at:  http://www.who.int/wer/2014/wer8914.pdf?ua=1

 

EDITORIAL NOTE

Despite substantial progress and a dramatic reduction in estimated measles mortality of 88% in AFR from 354,900 to 41,400 during 2000–2012, the measles 2012 pre-elimination goal was not reached. Major outbreaks occurred during 2009–2010 and since then reported measles cases have remained above the historic low of 37,012 cases in 2008. During 2011–2012, large outbreaks occurred in a small number of member states; 89% of cases in 2011 were from 4 member states (Chad, DRC, Nigeria and Zambia) and 88% of cases in 2012 were from 5 member states (Angola, Burkina Faso, DRC, Ethiopia, and Nigeria). Various outbreak investigation activities done in these outbreaks indicated the predisposing causes were an accumulation of susceptible older children and adolescents, shifting susceptibility towards older age groups, and continued gaps in reaching all children with 2 doses of measles vaccine at national and subnational levels through routine vaccination or periodic follow-up SIAs.

Annual measles cases in AFR reported through the JRF have been consistently higher than those reported through case-based surveillance. According to WHO guidelines, the total number of confirmed cases reported to the measles case-based surveillance system should match the total number of measles cases reported through the JRF. In 2012, 13 member states reported considerably more cases through the JRF than case-based surveillance. These differences might be due to classification errors, reporting errors, or reliance on aggregate summary reporting of notifiable diseases through the Integrated Disease Surveillance and Response system. Limited implementation of case based surveillance in some health facilities, incomplete preparation and reporting of line lists during outbreaks, and insufficient personnel to enter all surveillance data into databases may contribute to underreporting through measles case-based surveillance.

The proportion of member states meeting both casebased surveillance performance indicators increased from 35% in 2009 to 44% in 2012. Measles surveillance systems in member states not attaining objectives for surveillance indicators might lack the sensitivity to rapidly detect and respond to outbreaks. Monitoring district- level surveillance performance indicators can help member states to identify prioritize support for areas needing to improve performance. Conducting adequate outbreak investigations could rapidly identify and characterize outbreaks and guide the response activities.

The findings in this report are subject to at least 3 limitations. First, MCV coverage estimates likely include errors from inaccurate estimates of the size of target populations, inaccurate reporting of doses delivered, and inclusion of SIA doses given to children outside the target age group. Second, surveillance data underestimate the true number of cases because not all patients with measles seek care, and not all of those who seek care are reported. Finally, some member states also maintain multiple reporting systems for measles and might report in the JRF aggregate, unconfirmed cases rather than confirmed cases generated from case-based surveillance.

The Global Vaccine Action Plan and the Measles and Rubella Initiative (MRI) Strategic Plan provide key strategies and targets for measles elimination in 5 WHO regions by 2020. In September 2011, the WHO Regional Committee for Africa established as a goal the elimination of measles by 2020. The African Regional strategic plan for measles elimination (2012–2020) outlines the key programmatic focus, and the strategies to apply in order to achieve measles elimination. In AFR member states, intensified efforts to increase coverage with 2 doses of MCV include implementing updated policies to decrease missed opportunities, including opening multi-dose vials even when few eligible children are present, immunizing unvaccinated children up to 5 years of age through routine immunization services, sustaining the implementation of the ‘reaching every district’ approach, using SIAs to improve routine immunization services, and introducing a second dose in the routine immunization schedule once the eligibility criteria are met. To ensure high population immunity, member states should also conduct high-quality, well-monitored SIAs, that are routinely evaluated through coverage surveys. SIA target age groups should be based on national measles epidemiology determined by surveillance and immunization data.

Member States are encouraged to mobilize adequate additional resources to complement the funding from the global partners in order to achieve their goal of measles elimination. In addition to funding from the MRI and other organizations, the GAVI Alliance is providing funding to support the introduction of a second dose of measles vaccine in routine immunization, measles SIAs in Chad, DRC, Ethiopia and Nigeria, and the introduction of rubella vaccine through wide-age range measles-rubella vaccination campaigns.