Asymptomatic infections are defined as patients who have no significant discomfort of their own, or no clinically recognizable signs and symptoms, but who have positive pathogenic tests or other laboratory findings. Therefore, asymptomatic infected patients usually do not have detectable clinical manifestations, much less ten symptoms. If the infection increases in severity, typical symptoms of the associated disease may develop. Many pathogenic infections can present asymptomatic cases, such as streptococci, hepatitis B virus, human immunodeficiency virus, novel coronaviruses, and protozoan infections. Asymptomatic infections are also somewhat infectious. Asymptomatic patients with novel coronavirus infection may have different clinical regression after antiviral treatment. Some infected patients may have negative nucleic acid after treatment, while others may become common cases with clinical manifestations such as fever, malaise, dry cough, muscle aches, etc. Carriers of hepatitis B virus have no obvious signs and symptoms, which can be confirmed by HBV testing and liver function tests. Some patients have a persistent carrier status, and a small number of them can be transformed into active lesions, with manifestations of liver function damage such as elevated transaminases, liver palms, spider nevi, and even ascites. The same is basically true for asymptomatic infections with other pathogens. Because some pathogens are infectious, asymptomatic infections are not off-limits for treatment, and individuals who are tested for the presence of infection should actively receive treatment.