Some people with COVID-19 experience no symptoms whatsoever throughout the entire course of their infection. Learning how much these persistently asymptomatic individuals contribute to the spread of COVID-19 could shed light on the transmission of this virus and help us understand the illness severity spectrum seen in this disease, where some people have no symptoms while others develop fatal illness.

In a paper published online on December 7 in Lancet Infectious Diseases, Eric Meyerowitz, M.D., and colleagues contend that what’s currently known about asymptomatic individuals is likely to be wrong. They describe three problems that interfere with efforts to better understand asymptomatic people and their role in fueling new COVID-19 cases: incomplete assessment of symptoms overestimates the number of asymptomatic individuals; people who do show symptoms eventually may be misclassified as asymptomatic if not followed long enough; and assessment of antibody responses may identify people with previously unrecognized infection, but misclassification may result by relying on poorly defined antibody responses as well as retrospective symptom assessment.

Dr. Meyerowitz is an assistant professor of medicine at Albert Einstein College of Medicine and an attending physician at Montefiore.