(Bloomberg) -- New guidance from the U.S. Centers for Disease Control and Prevention for the upcoming holiday season warns that hosts and attendees at holiday celebrations will need to take steps to limit the risk of contracting and spreading the novel coronavirus.

Virtual gatherings or those that involve one’s immediate household are low risk, the agency said in a posting Monday. If people do gather in person for Christmas and other holidays, the CDC recommends doing so outdoors, keeping groups small, using measures like mask-wearing and social distancing, and considering local virus conditions as well as where attendees are coming from.

Instead of communal, potluck-style food, hosts can ask attendees to bring their own, the CDC said. Cutting down on shared items by having one person serve, and getting single-use plates and condiments, are also recommended, according to the CDC.

Traditional celebrations like Halloween trick-or-treating, large indoor Día de los Muertos gatherings, crowded Thanksgiving parades and Black Friday shopping sprees could spread the virus and should be avoided, according to the guidance. The CDC recommends alternatives such as virtual Halloween costume contests, holding a small dinner for household members and shopping online.

Those with a confirmed Covid-19 case or for whom illness is suspected shouldn’t host or attend holiday gatherings, while those who are at-risk should avoid in-person gatherings or try to mitigate risk at those events, the agency said.

(Updates to include date of CDC posting in second paragraph)

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