Even as the coronavirus disease 2019 (COVID-19) pandemic continues to threaten the world with resurgences in many countries, the risk posed by various degrees of infection, from asymptomatic through presymptomatic to symptomatic infection with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is still undefined.
A new preprint, available on the medRxiv* server, describes how researchers found at least a third of infected individuals to be asymptomatic, but that a fifth of them successfully passed on the virus to others. In comparison, about a quarter of symptomatic cases did so, especially when the symptoms included fever, cough and shortness of breath. In these circumstances, up to 30% of them transmitted the virus.
