Abstract
Measles is a highly contagious and severe disease. Despite mass vaccination, it remains a leading cause of death in children in developing regions, killing 114,900 globally in 2014. In 2006, China committed to eliminating measles by 2012; to this end, the country enhanced its mandatory vaccination programs and achieved vaccination rates reported above 95% by 2008. However, in spite of these efforts, during the last 3 years (2013–2015) China documented 27,695, 52,656, and 42,874 confirmed measles cases. How measles manages to spread in China—the world’s largest population—in the mass vaccination era remains poorly understood. To address this conundrum and provide insights for future public health efforts, we analyze the geospatial pattern of measles transmission across China during 2005–2014. We map measles incidence and incidence rates for each of the 344 cities in mainland China, identify the key socioeconomic and demographic features associated with high disease burden, and identify transmission clusters based on the synchrony of outbreak cycles. Using hierarchical cluster analysis, we identify 21 epidemic clusters, of which 12 were cross-regional. The cross-regional clusters included more underdeveloped cities with large numbers of emigrants than would be expected by chance (p = 0.011; bootstrap sampling), indicating that cities in these clusters were likely linked by internal worker migration in response to uneven economic development. In contrast, cities in regional clusters were more likely to have high rates of minorities and high natural growth rates than would be expected by chance (p = 0.074; bootstrap sampling). Our findings suggest that multiple highly connected foci of measles transmission coexist in China and that migrant workers likely facilitate the transmission of measles across regions. This complex connection renders eradication of measles challenging in China despite its high overall vaccination coverage. Future immunization programs should therefore target these transmission foci simultaneously.
Highlights
Measles is a highly contagious disease caused by the measles virus, a paramyxovirus, genus Morbillivirus
We characterize the geospatial distribution of measles and epidemic connections among cities across China
Using incidence data reported during 2005–2014 for all 344 cities in China, we show that the municipal burden of measles differed substantially and some cities were highly connected and experienced synchronous outbreaks
Summary
Measles is a highly contagious disease caused by the measles virus, a paramyxovirus, genus Morbillivirus. Before vaccine licensure in 1963, the disease infected virtually all children. Since the implementation of mass vaccination programs, the number of measles infections has declined dramatically and many countries have declared elimination of the disease [2,3]. Measles remains a leading cause of death among young children in developing regions, despite immense public health efforts [2,4]. Due to decreases in vaccination coverage and importation of cases through travel, the re-emergence of measles has become a concern in recent years for regions free of measles [2,3,6,7]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
