[Contribution of asymptomatic and pre-symptomatic cases of COVID-19 in spreading virus and targeted control strategies].

The asymptomatic carrier state of COVID-19 has become a topic of concern for preventing the rebound of possible epidemic. This review describes and defines the COVID-19 asymptomatic carrier state and outlines the methods for identifying, counting and reporting of these cases. The author elaborates that the asymptomatic carrier state can be further divided into asymptomatic infection and pre-symptomatic infection after extended follow-up based on the nature of the disease progression. The author presents the limited available data about the infectivity of asymptomatic and pre-symptomatic cases and their possible contributions to the overall epidemic of COVID-19 observed so far in China. Challenges of a possible second epidemic wave of COVID-19 caused by asymptomatic and pre-symptomatic cases are discussed and suggestions for control strategies and scientific research are provided.