Epidemiological features of and changes in incidence of infectious diseases in China in the first decade after the SARS outbreak: an observational trend study

Abstract

Background: The model of infectious disease prevention and control changed significantly in China after the outbreak in 2003 of severe acute respiratory syndrome (SARS), but trends and epidemiological features of infectious diseases are rarely studied. In this study, we aimed to assess specific incidence and mortality trends of 45 notifiable infectious diseases from 2004 to 2013 in China and to investigate the overall effectiveness of current prevention and control strategies.

Methods: Incidence and mortality data for 45 notifiable infectious diseases were extracted from a WChinese public health science data centre from 2004 to 2013, which covers 31 provinces in mainland China. We estimated the annual percentage change in incidence of each infectious disease using joinpoint regression.

Findings: Between January, 2004, and December, 2013, 54 984 661 cases of 45 infectious diseases were reported (average yearly incidence 417·98 per 100 000). The infectious diseases with the highest yearly incidence were hand, foot, and mouth disease (114·48 per 100 000), hepatitis B (81·57 per 100 000), and tuberculosis (80·33 per 100 000). 132 681 deaths were reported among the 54 984 661 cases (average yearly mortality 1·01 deaths per 100 000; average case fatality 2·4 per 1000). Overall yearly incidence of infectious disease was higher among males than females and was highest among children younger than 10 years. Overall yearly mortality was higher among males than females older than 20 years and highest among individuals older than 80 years. Average yearly incidence rose from 300·54 per 100 000 in 2004 to 483·63 per 100 000 in 2013 (annual percentage change 5·9%); hydatid disease (echinococcosis), hepatitis C, and syphilis showed the fastest growth. The overall increasing trend changed after 2009, and the annual percentage change in incidence of infectious disease in 2009-13 (2·3%) was significantly lower than in 2004-08 (6·2%).

Interpretation: Although the overall incidence of infectious diseases was increasing from 2004, the rate levelled off after 2009. Effective prevention and control strategies are needed for diseases with the highest incidence-including hand, foot, and mouth disease, hepatitis B, and tuberculosis-and those with the fastest rates of increase (including hydatid disease, hepatitis C, and syphilis).

Funding: Chinese Ministry of Science and Technology, National Natural Science Foundation (China).

Figure 1

Incidence and case-fatality ratios of 45 infectious diseases, by sex and age (A) Overall yearly incidence of 45 infectious diseases, by sex and age. (B) Overall yearly case-fatality ratios of 45 infectious diseases by sex and age. (C) Incidence of 45 infectious diseases by sex and age. Infectious diseases are grouped according to whether they had high incidence among children (group A), high incidence among adults (group B), increasing incidence trends by age and especially significant among men (group C1), high incidence among males in all age groups (group C2), high incidence among middle-aged men (group C3), and no significant features in terms of incidence by sex and age (group D). (D) Case-fatality ratios of 45 infectious diseases by sex and age. Infectious diseases are grouped according to whether they had no fatality in any age group (group A), high case-fatality ratios among children (group B), high case-fatality ratios among young people and middle-aged adults (group C), high case-fatality ratios among elderly people (group D), increasing trends in case-fatality ratios with age (group E), and no significant features in terms of case-fatality ratios by sex and age (group F). The incidence and case-fatality ratio for each infectious disease were standardised from 0 to 1 according to percentile rank, and represented by the colour scale (from 0 to 1; where 1 is the highest rate and 0 is the lowest rate). AD=amoebic dysentery. AHC=acute haemorrhagic conjunctivitis. BD=bacterial dysentery. ECM=epidemic cerebrospinal meningitis. HFMD=hand, foot, and mouth disease. NT=neonatal tetanus. OID=infectious diarrhoeal diseases other than cholera, bacterial dysentery, amoebic dysentery, typhoid, and paratyphoid. SARS=severe acute respiratory syndrome.

Figure 2

Joinpoint regression showing trends in overall incidence of 45 infectious diseases (A) Trend in overall incidence from 2004 to 2013. Red line denotes the overall incidence and orange shading denotes the 95% CI. Blue line denotes observed incidence. Solid vertical line at 2009 denotes the end of the first 5 years of the study and the beginning of the second 5 years. (B) Yearly APC in incidence and overall trend, from 2004 to 2008. Red squares denote the observed values and green line the slope of the APC. (C) Yearly APC in incidence and overall trend, from 2009 to 2013. Red squares denote the observed values and green line the slope of the APC. APC=annual percentage change.

Figure 3

Trends in incidence for 45 infectious diseases, from 2004 to 2013 Every concentric circle represents 1 year, starting with 2004 in the centre. Infectious diseases are grouped according to emerging status (group A), increasing (group B) or decreasing (group C) trends, or stable status (group D). The incidence and case-fatality ratio for each infectious disease were standardised from 0 to 1 according to percentile rank, and represented by the colour scale (from 0 to 1; where 1 is the highest rate and 0 is the lowest rate). HFMD=hand, foot, and mouth disease. AD=amoebic dysentery. AHC=acute haemorrhagic conjunctivitis. BD=bacterial dysentery. ECM=epidemic cerebrospinal meningitis. NT=neonatal tetanus. OID=infectious diarrhoeal diseases other than cholera, bacterial dysentery, amoebic dysentery, typhoid, and paratyphoid. SARS=severe acute respiratory syndrome.

Figure 4

Trends in incidence and case-fatality ratios of infectious diseases in different geographic areas of China (A) Incidence trends of the 45 infectious diseases in different Chinese provinces. The infectious diseases with the highest average incidence were distributed across the indicated provinces. Infectious diseases with increasing trends from 2004 to 2013 are presented in red; those with decreasing trends are in blue; and stable diseases are shown in black. (B) Case-fatality ratios of infectious diseases in different Chinese provinces. ECM=epidemic cerebrospinal meningitis. HFMD=hand, foot, and mouth disease. OID=infectious diarrhoeal diseases other than cholera, bacterial dysentery, amoebic dysentery, typhoid, and paratyphoid. SARS=severe acute respiratory syndrome.