Epidemiologic characteristics of scarlet fever in Shanghai, 2005-2015

Objective To understand the epidemiologic characteristics of scarlet fever in Shanghai from 2005 to 2015 and provide evidence for the prevention and control of scarlet fever. Methods Descriptive epidemiologic analysis was conducted on the spatial, temporal and population distributions of scarlet fever cases reported in Shanghai from 2005 to 2015 by using the data from National Notifiable Disease Reporting System. Results During 2005-2015, a total of 19 510 scarlet fever cases were reported in Shanghai. The incidence was lowest in 2010 (2.19/100 000) and highest in 2015 (19.41/100 000).The number of reported cases and annual incidence in 2015 were 6.40 and 4.69 times higher than those in 2005. More than 79.00% of the cases occurred during March-June and during November-January. Over 93.00% of the cases were aged 3-15 years and more than 90.00% of the cases were school-aged children or children in child care settings. The ratio of male to female was 1.69 : 1. After 2011, the proportion of laboratory-confirmed cases remained to be about 50.00%. Conclusion Both of the reported cases and incidence of scarlet fever increased during 2005-2015 in Shanghai, but two epidemic peaks occurred in 2011 and 2015. It is necessary to strengthen the pathogenic surveillance, including strain type, virulence and drug sensitivity of the pathogen. Meanwhile, more attention should be paid to susceptible population and health education before and during the epidemic seasons.