SAN FRANCISCO — At the Latin American Club on Monday night, the rule was already in effect.

Bouncer Jason Voisine, 54, asked patrons for proof of vaccination at the San Francisco bar known for its stiff margaritas. A photo of the vaccination record, he said, would do just fine.

“You’re going to see a lot of bars doing this now,” he warned.

Indeed, starting Thursday, hundreds of San Francisco bars will require patrons to show proof of vaccination or a negative coronavirus test before they can drink inside. It was a decision made Monday by the San Francisco Bar Owner Alliance, a coalition of more than 500 bars in the densely populated city. While it’s up to individual bars to participate, most members have opted in, Ben Bleiman, the organization’s founder, told The Washington Post.

“Let’s be clear here,” Bleiman said in a phone interview. “We are doing this because we need to protect our staff and their families and our customers.”

Bleiman, who owns several bars around the city, said the idea came three weeks ago when he and other owners saw a “very concerning surge” of vaccinated bar workers coming down with the virus. “You could see the writing on the wall,” he said. “It was happening left and right.”

To some, carrying a card to verify you've had a vaccination seems like a foreign concept. But vaccine cards, or yellow cards, have been used for decades. (Allie Caren/The Washington Post)

Last Wednesday, Bleiman had to close one of his bars, Soda Popinski’s, because a vaccinated employee had contracted the virus at another job. After more than a year of suffering during the pandemic, he said, San Francisco bar owners do not want to subject themselves to the types of restrictions that were in place before the vaccine rollout. Until this summer, bars operated at limited capacity or remained completely closed down.

Now, he said, things are different: “We know how to control the virus.”

The move comes as vaccination rates across the country have lagged while infections are back on the rise.

Confirmed cases nationwide have quadrupled, from an average of 13,000 cases per day at the beginning of the month to more than 55,000 now, according to The Post’s tracking. In California, nearly 3,000 coronavirus cases are now severe enough to require hospitalization, versus 900 in mid-June, due to the highly transmissible delta variant, Mark Ghaly, California’s health secretary, told The Post this week.

Meanwhile, about half of U.S. adults are fully vaccinated, according to The Post’s tracking. The low rates have prompted some organizations to require vaccines. The Department of Veterans Affairs said on Monday that it will require its front-line workers to receive a vaccine. The Mayo Clinic announced it will implement a similar policy.

And, now, San Francisco bars will ask for vaccination cards.

Mike Krouse, the owner of Madrone Art Bar on Divisadero Street, said three of his employees, all fully vaccinated, contracted the virus in early July.

Last weekend, Krouse asked patrons if they had been vaccinated, and several said they had not. “The question I asked them is, ‘Why do you want to be here? Why do you want to be in this environment?’” he said, noting that it is easier to catch the virus in a room packed with people.

His bar began checking for proof of vaccination on Monday. So far, he said, the response has been “overwhelmingly positive from my customer base.” But that hasn’t stopped some anti-vaccine advocates from “blowing up” his social media channels. “Either way I go, I’m going to get heat,” he said.

For Ali Razavi, owner of the 500 Club, asking for proof of vaccination is about “solidarity” with the rest of San Francisco’s bars. And he knows that means turning people away, potentially losing business and facing some criticism.

“There’s going to be a cost associated with it,” he said. “There’s going to be people who are going to throw their hats in their air and argue about it and call us names.”

But, he said, getting into bars should be easy if you are vaccinated. Some places, like the Latin American Club, will accept photos of a vaccination record. He noted that in California, it’s easy to call up your vaccination record online.

Razavi said bar employees will use their best judgment when determining the authenticity of vaccination cards. “We’re not going to decipher between the typeset on that card versus the other. A lot of this is an honor system.”

Over at the Lone Palm on 22nd Street, the crowd was sparse. Most patrons nursed drinks over white tablecloths and under flickering candles. Helena Antonowitsch, 45, had just walked in with a few friends and ordered a vodka martini with a twist of lemon. She had heard the news of San Francisco bars requiring proof of vaccination.

“It’s a good thing,” she said, noting that she was vaccinated. “I don’t want to be around people who aren’t vaccinated, and we should protect our workers because they’ve been exposed more than anyone — so I’m all for it.”

At the Latin American Club, Chris Joseph, 42, was standing at the bar, drinking a tequila and soda. He was also happy about the policy. He’s an events producer and said the pandemic devastated him and his industry. “If we can’t gather, we can’t work,” he said. “And if we can’t prove that there’s safety, it affects me and my people dramatically.”

Bleiman, of the San Francisco Bar Owner Alliance, had a message for those who argue that requiring vaccines to enter businesses infringes on people’s rights: “American freedom is not the freedom to do whatever you want. American freedom is the freedom to do anything as long as it doesn’t put other people in harm’s way.”

To think otherwise, he said, is “absurdly narcissistic and selfish — and the bar owners are tired of it.”

The White House said on July 26 that it supported the call by U.S. medical associations for employers to mandate vaccines for health-care workers. (Reuters)