Two studies published late last week in The Lancet Infectious Diseases characterize COVID-19 passengers on the Diamond Princess cruise ship, one finding that some infected patients have a lung infection with viral shedding but no symptoms, and the other suggesting that advanced age, severe lung involvement, and reduced lymphocyte count are risk factors for disease progression.Cruise ships are a unique, confined environment that simulate the living conditions and social interactions of a city, offering researchers the chance to define viral shedding patterns and patient antibody responses before and after symptom onset in a mostly older population with different ethnicities and immunization and health statuses, the authors of the first study