In crowded settings, social distancing (that is, measures that increase the physical space between people and reduce their frequency of close contact) is difficult to maintain. Moreover, at public gathering events that are celebratory in nature (such as weddings, graduation ceremonies), participants frequently have social personal contact (like handshaking and hugging). As a result, there may be increased risk for spread of novel influenza A (H1N1) virus among attendees of such events and subsequent spread of illness in the community or in communities to where attendees return. The recommendations below are intended to reduce the spread of influenza infection in communities.