It is has been the history of the Diocese not to mandate any liturgical adaptions during flu season, but to reinforce good and reasonable health habits. Pastors are asked to not withhold receiving the Precious Blood from the Chalice or disregard the Sign of Peace.
Parish staff are encouraged to remind parishioners via announcements and the bulletin about actions that are not only prudent but also express care and concern for the entire congregation. If someone feels sick, then s/he should stay home to avoid possible contamination to others. If anyone is coughing or has the sniffles, that person should refrain from receiving the Precious Blood from the common cup. Frequent hand washing and/or use of alcohol-based anti-bacterial solutions are helpful. If a person chooses not to offer the Sign of Peace in the form of a handshake, then it would appropriate to simply acknowledge others in the form of a bow. Attention should be given to cleaning and regularly replacing water in any holy water fonts.
Further information can be found on the USCCB website here.