The coronavirus disease 2019 (COVID-19) epidemic has become a pandemic. Although the current epidemic has been effectively contained in China, the prevention and control are still facing great pressure. As a potential source of infection, healthy carriers and latent carriers play important roles in the spread of the epidemic. Some issues are of great significance for the prevention and control of the current epidemic situation, including high-quality epidemiological investigations, detection of viral nucleic acids in specific populations, and small-scale screening in locations where COVID-19 cases occur more frequently, as well as strengthening the horizontal communication among the different clustered epidemic investigations. Clear understanding of the spectrum of infection, infection period, carriers in recovery period, nosocomial infection and the length of incubation period of COVID-19 can help to take targeted measures in the future prevention and control work of this epidemic.