Version: April 2024
Influenza, commonly known as the flu, is a highly contagious viral infection often confused with a common cold due to similar symptoms. It primarily affects the respiratory system, causing fever, sore throat, muscle aches, cough, and fatigue. There are four types of influenza - A, B, C, and D. Influenza A and B are most common in humans and pose serious public health risks, leading to annual epidemics. The virus is primarily spread through tiny droplets when infected people talk, sneeze, or cough, and can also be contracted by touching infected surfaces.
Over the years, there was a steady rise in influenza cases in the Chinese mainland up until 2018, which had a sudden influx peaking in January 2019. Things slightly declined but surged again in December 2019. The case counts fluctuated but maintained a high range in the early parts of 2020, before declining around March 2020. From April 2020 to November 2021, cases remained relatively low before spiking again in December 2021 and January 2022. However, the most significant surges were recorded in March, November, and December 2023 following a slight decline earlier in the year.
While the case counts were rising, the death toll from influenza during this period remained relatively low. Even during the highest months of reported cases, the numbers of deaths remained in single or low double digits, peaking in January 2019 with 143 deaths. Despite the considerable case count fluctuations from 2020 to 2024, the deaths generally remained below ten each month, except for in the month of March 2023, where there were 38 deaths. This reveals an overall low fatality rate despite the high incidence of influenza.