Two unnamed bus drivers at in Nassau County have tested positive for the coronavirus, and will continue to be monitored over the week. The New York City Health Department issued an advisory warning that a person with confirmed coronavirus infection should exercise caution and avoid traveling to work without medical supervision.

Additionally, the school’s medical director also notified the parents of students who may have been in close proximity with the bus drivers. Their identities are being withheld for now due to privacy concerns.

“The main thing we can say is that both drivers are being monitored at the present time and that we are treating this as signs of a serious potential outbreak. We have no idea to what extent the illness is spreading but it is vitally important we focus on containing it as much as possible to reduce community spread” Nassau County Executive Laura Curran said at a news conference today.

This is the first major outbreak in Nassau County after a Manhattan-based lawyer was diagnosed with the coronavirus in Westchester after showing symptoms such as coughing, sneezing and shortness of breath.

The administration of Mayor Bill de Blasio plans to implement measures to limit the outbreak of coronavirus within New York City limits, aimed largely to protect active and retired city employees and retired school bus drivers, officials said.

It’s unclear how soon the measures will be implemented, but the city would make further announcements available when available, said Eric Beaton, the city’s deputy commissioner of transportation