Epidemiological characteristics of hand, foot and mouth disease reinfection in Guangzhou, Southern China from 2012 to 2017

Background: Hand, foot and mouth disease (HFMD) is a common infectious disease that occurs mostly in infants and children. Reinfection is not uncommon because of the limited cross-protection from infections of different enterovirus. This study was to investigate the epidemiological characteristics and its influential factors of HFMD reinfection in Guangzhou. Methods: Data on HFMD patients aged ≤5 years from 2012 to 2017 were extracted from surveillance system. Descriptive epidemiology method was adopted to analyze the characteristics of populations and time. Influential factors of reinfection were assessed using the logistic regression model. Results: Of 369,054 HFMD patients, 11,321 patients were classified as reinfection, corresponding to a rate of 3.07%. The reinfection rate in male was higher than in female (χ2=60.11, P<0.001). The reinfection rate in patients ≤1 year was 3.86%, which showed a downward trend with age (Z=37.37, Ptrend<0.001). The highest reinfection rate was observed in the scattered children (3.38%), followed by nursery care children and others (χ2=514.75, P<0.001). Besides, higher risk of reinfection was detected among those who were male, lower age group and other enteroviruses infection compared with their respective counterparts. Seasonality was illustrated according to the number of reinfections peaked from April to July. Time intervals curves revealed the number of reinfections gradually increased after 13 months from the initial infection. Conclusions: These results indicated that male ≤4 years, especially those lived scattered and infected with other enteroviruses were more likely to be reinfection. Administrations need to be alert to signs of HFMD reinfection. Effective interventions should be imposed on these high-risk children in time.