Public health experts are warning that COVID-19 is spreading in bars and nightclubs, as young people emerge from months of isolation to drink and socialize, The New York Times reports.

Bars have recently been ordered shut in states including Texas, Arizona, Colorado and California.

Bars pose a higher risk than restaurants, because they are often smaller and narrower, the article notes. They tend to have fewer windows and weaker ventilation systems. People shout to be heard above loud music, which sprays more viral particles into the air. As people drink more, they may become more lax about masks and social distancing.

“The combination of all the factors — the age, alcohol, time of day, all those things come together to make it hard for even the most conscientious bar manager,” said Kris Ehresmann, Director of the Infectious Disease Epidemiology at the Prevention and Control Division at Minnesota’s Department of Health.