Application of the World Health Organization Programmatic Assessment Tool for Risk of Measles Virus Transmission—Lessons Learned from a Measles Outbreak in Senegal

Abstract

The World Health Organization (WHO) African Region set a goal for regional measles elimination by 2020; however, regional measles incidence was 125/1,000,000 in 2012. To support elimination efforts, the WHO and U.S. Centers for Disease Control and Prevention developed a tool to assess performance of measles control activities and identify high-risk areas at the subnational level. The tool uses routinely collected data to generate district-level risk scores across four categories: population immunity, surveillance quality, program performance, and threat assessment. To pilot test this tool, we used retrospective data from 2006 to 2008 to identify high-risk districts in Senegal; results were compared with measles case-based surveillance data from 2009 when Senegal experienced a large measles outbreak. Seventeen (25%) of 69 districts in Senegal were classified as high or very high risk. The tool highlighted how each of the four categories contributed to the total risk scores for high or very high risk districts. Measles case-based surveillance reported 986 cases during 2009, including 368 laboratory-confirmed, 540 epidemiologically linked, and 78 clinically compatible cases. The seven districts with the highest numbers of laboratory-confirmed or epidemiologically linked cases were within the capital region of Dakar. All except one of these seven districts were estimated to be high or very high risk, suggesting that districts identified as high risk by the tool have the potential for measles outbreaks. Prospective use of this tool is recommended to help immunization and surveillance program managers identify high-risk areas in which to strengthen specific programmatic weaknesses and mitigate risk for potential measles outbreaks.

Development of the World Health Organization Measles Programmatic Risk Assessment Tool Using Experience from the 2009 Measles Outbreak in Namibia

“…In addition to Windhoek, the districts most affected by the outbreak were in the north along the border with Angola, and were a mix of very‐high‐, high‐, medium‐, and low‐risk districts. There was no statistically significant correlation between risk category and measles incidence in Namibia, in contrast to the findings in Senegal and the Philippines . There are several factors that could have accounted for these results.…”

“…There was no statistically significant correlation between risk category and measles incidence in Namibia, in contrast to the findings in Senegal and the Philippines. (11,12) There are several factors that could have accounted for these results. The districts of Eenhana, Opuwo, and Kongo reported high incidence of measles during 2009 but were classified as medium-or low risk districts by the assessment; they were situated on the border of Angola, which was also experiencing a large ongoing measles outbreak during the assessment year.…”

Development of a District‐Level Programmatic Assessment Tool for Risk of Measles Virus Transmission

“…The tool was not designed to be predictive of measles outbreaks but rather to assess the level of risk for measles transmission in a district/area if virus were to be introduced, using key programmatic indicators. Comparisons of risk categories with historical outbreak data were performed in three countries used for prototype development, and the results showed correlation between districts with high scores and the occurrence of measles transmission during the following year in two of the three countries . Even if the tool has limited value in predicting outbreaks, results of the risk assessment can be used to guide measles elimination strategies and identify programmatic areas that require strengthening.…”

“…More details of the three countries used for prototype development and visual and statistical comparisons of risk categories with historical outbreak data are described elsewhere. (12)(13)(14)…”

Modeling and Managing the Risks of Measles and Rubella: A Global Perspective Part II

“…(3) Similar to the risk assessment tool previously developed for polio, (70) the second article (71) developed a district-level programmatic assessment tool for measles transmission risks. The third through seventh articles present applications of the risk assessment tool for countries in each of the WHO regions yet to eliminate measles: India, (72) Namibia, (73) the Philippines, (74) Romania, (75) and Senegal, (76) respectively. The last article (77) integrates many of the components presented in Part I into a dynamic transmission model for measles and rubella and it demonstrates the significant costs of delays associated with continuing control instead of eradication.…”