The Centers for Disease Control and Prevention does not mandate protective measures for the U.S., but as the coronavirus has spread it has provided more specific guidance for state and local authorities who do. The agency says the highest risk is taken by anyone who attends large indoor gatherings where six-foot "social distancing" is hard to maintain, where attendees may be singing or cheering without recommended face coverings and where some in the crowd may have traveled from other places.
"The more closely you interact with others, the longer the interaction lasts and the greater the number of people involved in the interaction, the higher the risk of COVID-19 spread," Dr. Jay Butler, a CDC deputy director, said. "The guideline is really for any type of gathering, whether it’s the backyard barbecue or something larger."