Epidemiological characteristics of the notifiable infectious diseases reported in Shanghai in 2020

Objective To understand the epidemic characteristics of notifiable infectious diseases （NIDs） other than coronavirus disease 2019 （COVID-19） in Shanghai in 2020， and to provide evidence for formulating infectious disease prevention and control strategies.

Methods Data of NIDs reported in Shanghai from 2015 to 2020 were collected through the National Information System for Disease Control and Prevention. Descriptive epidemiological methods were used to analyze the incidence and prevalence characteristics of NIDs in Shanghai in 2020， and compared them with the average values of 2015 to 2019.

Results A total of 45 574 cases of 23 kinds of NIDs were reported in Shanghai in 2020， except for COVID-19， with an incidence of 187.69/10⁵， and a decrease rate of 50.58% compared with the average value of 2015 to 2019. The incidence of category B and C infectious diseases decreased by 38.07% and 57.47%， respectively （All P<0.001）. The top 3 reported infectious diseases with the highest incidence rate were influenza （64.58/10⁵）， syphilis （39.09/10⁵） and tuberculosis （24.90/10⁵）. The incidence of most infectious diseases decreased compared with the average of 2015 to 2019， among which measles （97.15%）， rubella （88.81%）， pertussis （87.43%）， hand foot mouth disease （85.99%） and scarlet fever （79.84%） decreased significantly （all P<0.001）. In general， compared with the average from 2015 to 2019， respiratory infectious diseases declined most， followed by intestinal infectious diseases， insect-borne and natural focal infectious diseases， blood-borne and sexually transmitted diseases. Districts with higher incidence in 2020 were Fengxian District （310.23/10⁵）， Xuhui District （271.93/10⁵） and Hongkou District （254.38/10⁵）. Respiratory infectious diseases in Fengxian District， intestinal infectious diseases in Jinshan District， blood-borne and sexually transmitted infectious diseases in Changning District， and insect-borne and natural focal infectious diseases in Yangpu District showed the highest incidence rate. Incidence of infectious diseases in 16 districts of Shanghai decreased with different degrees （all P<0.001）. Incidence of infectious diseases in males （209.44/10⁵） was higher than that in females （164.89/10⁵） （χ²=624.864， P<0.001）. Children aged 0-9 years had the highest incidence of respiratory and intestinal infectious diseases. People aged 70‒79 years and 20‒29 years had higher incidence of blood-borne and sexually transmitted infectious diseases， and people aged 20‒29 years had the highest incidence of insect-borne and natural focal infectious diseases. Majority of the patients were students （8 327 cases， 18.27%）， retired people （6 393 cases， 14.03%） and unemployed household workers （5 988 cases， 13.14%）.

Conclusion Under the COVID-19 prevention and control policies， the incidence of most NIDs in Shanghai decreased significantly in 2020.