SEATTLE (AP) — At least 60 Seattle bars and restaurants as of Friday began requiring customers to prove they have been vaccinated as a requirement to eat or dine inside as the highly infectious COVID-19 delta variant spreads through Washington state.

The Seattle Times reports the self-imposed mandate includes Capitol Hill bars The Unicorn, Linda’s Tavern, Rumba and Canon, and comes as the state sees a fifth wave of infection.

At least a dozen bars temporary closed last week after their employees tested positive for COVID-19 or came into contact with an infected person. That led many bar owners to announce over social media that vaccination proof will be required to dine or drink on their premises.