In response to questions spurred by the current flu outbreak, the Diocese has issued this advisory:
With the guidance of the Bishop, it is the role of the pastor to judge whatever measures are needed to ensure the well-being of his parish community and to take every opportunity to remind the faithful that they should refrain from receiving Communion from the chalice if they are ill. The sick are not obliged to attend Mass and should use prudence and good judgment before coming into contact with others.
The U.S. Conference of Catholic Bishops maintains a page on its website devoted to the liturgy and influenza. It offers information about the flu as well as how to prevent the spread of any disease at liturgy.