From the Document: "Coronavirus disease 2019 (COVID-19) is a respiratory illness caused by a virus called SARS-CoV-2 [severe acute respiratory syndrome coronavirus 2]. Symptoms often include a fever, cough, or shortness of breath. [...] Recent studies indicate that the virus can be spread by people before they develop symptoms (pre-symptomatic) or who never develop symptoms (asymptomatic). It also may be possible that a person can get COVID-19 by touching a surface or object that has the virus on it and then touching their own mouth, nose, or possibly their eyes. However, this is not thought to be the main way the virus spreads. [...] For rail transit operators, potential sources of exposure include having close contact with a passenger with COVID-19, by contacting surfaces touched or handled by a person with COVID-19, or by touching your mouth, nose, or eyes."
Centers for Disease Control and Prevention: https://www.cdc.gov/