The epidemic has been going on for years.

The epidemic has been going on for 1 years. The epidemic began in February 20 19 and ended at the end of 20 19 to the end of 2022. As of March 22, 2024, more than one year has passed. In recent three years, COVID-19 has been constantly mutating, and the mutant strains such as Alpha, Beta, Gamma, Delta and Omicron have brought new challenges to epidemic prevention and control. With the constant variation and increasing infectivity of the virus, China can quickly find the source of infection and effectively cut off the transmission chain of the virus. Since the outbreak of COVID-19 in late October19, China has been saying "all due". The premise of this sentence is that every node in the virus transmission chain must be found.