Analysis of epidemic situation of key infectious diseases in summer of 2021 in China

Objective To assess the incidences of key infectious diseases in the summer of 2021 in China and provide reference and guidance for further surveillance, prevention and control of these infectious diseases in the summer of 2021. Methods The incidence data of notifiable infectious diseases from January to May 2021 in China collected from National Notifiable Infectious Disease Reporting System and the influenza surveillance system were analyzed and compared with the incidence data of the diseases during the same periods from 2017 to 2020 by experts to evaluate and predict the incidence trends of the key infectious diseases in summer 2021. Results As of May 23, 2021, a total of 2.47 million cases of notifiable diseases had been reported in China, a decrease of 5% compared with the same period in 2020 (2.60 million cases). After the exclusion of COVID-19 cases, the case number was 42% lower than that during the same period in 2019 (4.26 million cases) and 24% lower than the average of the same periods from 2017 to 2019 (3.24 million cases). A total of 7162 deaths had been reported in China, which was 39% lower than that during the same period in 2020 (11671 deaths) and 6% lower than the average of the same periods from 2017 to 2019 (7639 deaths). From January to May 2021, a total of 27 000 brucellosis cases were reported, which was 73% higher than that during the same period in 2020 and 70% higher than the average during the same periods from 2017 to 2019. The incidence of brucellosis in Inner Mongolia has increased rapidly since 2017, and the incidences of brucellosis in Ningxia and Gansu have been in increase since 2018. During this period, a total of 430 000 cases of hand foot and mouth disease (HFMD), including 433 severe cases, were reported, an increase of 985% and 1070% compared with the same period in 2020, a total of 15 dengue fever cases were reported, which was 86% lower than that during the same period in 2020 (110 cases), a total of 59 anthrax cases were reported, which was higher than that during the same period in 2020 (47 cases), a total of 107 000 influenza cases were reported, which was 90% lower than that during the same period in 2020 and a total of 11 cases of human infection with avian influenza virus were reported, which was slightly higher compared with the same period in previous years, all the human infections with avian influenza virus occurred sporadically. Conclusion The total case number of notifiable infectious diseases between January and May in 2021 was lower than those during the same periods in previous years, the incidence would continue to remain stable in this summer. It is predicted that the case numbers and the incidence intensities of brucellosis, HFMD, dengue and anthrax would continue to increase in this summer. The surveillance and early warning of these diseases should be strengthened.