Epidemiological characteristics and spatiotemporal clustering of hepatitis A in Yuxi, Yunnan, 2005−2020

  Objective  To analyze the epidemiological characteristics and spatiotemporal clustering of hepatitis A in Yuxi prefecture, Yunnan province, during 2005−2020, and suggest countermeasures for hepatitis A prevention and control.

  Methods  The incidence data of hepatitis A in Yuxi from January 1, 2005 to December 31, 2020 were downloaded from National Notifiable Disease Report System. The population, time and space distributions of hepatitis A cases was described, the seasonality of hepatitis A incidence was analyzed using improved muster method, and the Poisson regression models was used to compare the reported incidence of hepatitis A in different age groups. The data during 2005−2008 (before the inclusion of hepatitis A vaccine into immunization program) and during 2009−2020 (after the inclusion of hepatitis A vaccine into immunization program) were used in the analysis. Software GeoDa 1.14 was used in global and local spatial autocorrelation analyses, and software SaTScan 9.7 was used in spatiotemporal scanning analysis.

  Results  A total of 1451 hepatitis A cases were reported in Yuxi during this period, the average annual incidence rate was 3.92/100 000, the incidence rate decreased from 8.36/100 000 in 2005 to 1.60/100 000 in 2020 (trend χ²=456.272, P<0.001), no obvious seasonality of the incidence of hepatitis A was observed except 2005 and 2012. The median of age of the cases showed an increasing trend (P=0.004), and the incidences showed decreasing trends in age group 0–9, 10–19 and 20−59 years (all of the P<0.001). From 2011 to 2020, the incidence risk was higher in age group ≥20 years than in age group 0−9 years (all RR>1, P<0.05). The average incidence increased gradually from the west to the east, but increased then decreased gradually from the north to the south in Yuxi. The local spatial autocorrelation analysis showed that the high-high clustering areas at tow level were Jiulong, Sijie and Gaoda in Tonghai county from 2005 to 2008 and Sijie in Tonghai county from 2009 to 2020. The spatiotemporal scanning analysis revealed that there were spatiotemporal clustering areas in 2007 and 2010, and the spatiotemporal clustering areas changed from type Ⅱ in 2007 to type I in 2010.

  Conclusion  The incidence of hepatitis A decreased in Yuxi from 2005 to 2020 and the incidence peaked gradually in older age group. The spatiotemporal clustering areas were observed in the central and southeast areas of Yuxi, specific prevention and control strategy is needed to reduce the incidence of hepatitis A.