Which statement best reflects norovirus shedding in asymptomatic infections?

• A. Asymptomatic individuals do not shed virus
• B. Asymptomatic individuals may shed high levels of virus
• C. Shedding occurs only during symptomatic illness
• D. Shedding occurs only in immunocompromised individuals

Answer: (B)

Asymptomatic carriage of norovirus can involve substantial viral shedding, which drives transmission even when no symptoms are present. People without symptoms can shed virus in stool for days (and sometimes longer), and the amount shed can be high—sometimes similar to what you see in those who are visibly ill. This is why asymptomatic individuals are an important source of spread, especially in crowded settings.

So the best statement is that asymptomatic individuals may shed high levels of virus. It’s not correct to say they do not shed at all, nor that shedding happens only during illness, nor that shedding is limited to immunocompromised people (healthy individuals can shed as well, though duration may be longer in some).