From Statistic to Holistic: An Analysis of Measles Elimination in Sindh, Pakistan Based on 2017 Infection Dynamics and Professional Opinion

Abstract

As one of the last few countries where smallpox existed, and now as one of the last few where polio exists, Pakistan is a significant place to study infectious disease. In fact, the reported measles cases in Pakistan today have tripled the numbers reported in 2011, the majority of which originate in Sindh province. This study analyzed real-time measles case data from VPD surveillance in Sindh for the first 20 weeks of 2017 and aggregate full-year case data to improve our understanding of measles dynamics in Pakistan by illuminating (1) measles characteristics and transmission trends of cases via "hotspot" analysis, a novel technique for case analysis in Sindh, and (2) factors contributing to the spread of measles by regressing prevalence and urbanicity against relevant covariates. Additionally, (3) opinions of Pakistani health-professionals on measles elimination were highlighted by distributing and analyzing responses to an opinion survey on the topic. R coding and ArcGIS were used to create maps and analyze trends in case data, and Qualtrics and Stata were used to analyze trends in survey data. Results demonstrate a large range of average age of onset among tehsils, with a provincial average age of 2.97 years. Hotspot results suggest that Badin, Talhar, and Shaheed Fazli Rahu serve as the biggest areas of concern for increased risk of infection and transmission. Additionally, a negative correlation between measles prevalence and urbanicity suggests that recent vaccinations in Karachi and Hyderabad have been effective. The lack of a significant negative correlation between vaccination coverage and measles prevalence, which has been evident in numerous previous studies, indicates bias with current methods of vaccination coverage calculation. Survey results suggest Pakistani professionals are largely optimistic (97.3% of all respondents) about the possibility of measles elimination and have identified inefficiencies with routine immunization as the major hindrance to measles elimination. This study calls on changes to current vaccination and surveillance strategies, including the use of a relatively new field-based electronic surveillance system known as eDEWS. Though limited by the lack of data on seasonal variation, migration, violence, the short time-scale of data obtained, and relatively low number of respondents in the survey, this study uses various statistical analyses and a qualitative assessment of behavior to provide a more holistic picture of the many factors influencing the story of measles in Pakistan today.