At an Orange County Board of Supervisors meeting, some speakers called the COVID-19 vaccine a “bioweapon.” They suggested that if they refused the shot, public officials would prohibit them from buying food and water.

As Andrew Do, the board chairman, celebrated a milestone of 1.2 million doses in the arms of residents, they hissed and booed.

Strident anti-mask, anti-vaccine rhetoric has become increasingly routine at public meetings nationwide during the pandemic.

But at the July 27 meeting in Orange County, a man in a gray beanie and dark sunglasses crossed a different line.

“You come to my country, and you act like one of these communist parasites. I ask you to go the f— back to Vietnam,” he yelled at Do, who is Vietnamese American.

Several attendees cheered.

Between anti-lockdown rallies, pushback against mask mandates and a restaurant catering to the unvaccinated, Orange County has seized the spotlight as a nexus of aggressive COVID-19 denialism.

The ratcheting up of incivility and racism comes at a time when pandemic fatigue is worsening and concerns about the Delta variant of the coronavirus have prompted a return to mask wearing, as well as discussions about vaccination requirements.

Month after month, the protesters have gathered outside the O.C. supervisors’ chambers, chanting, waving signs evoking Holocaust imagery and calling for the firing of the top public health official, Clayton Chau. They have also protested outside public officials’ homes.

For them, former President Trump’s statements demonizing immigrants and blaming China for unleashing the coronavirus are a backdrop and an inspiration.

In a county that has evolved from mostly white roots to become majority Asian and Latino, racism is still an ugly undercurrent in politics and in daily life.

Vietnamese-language radio and television shows aired a video of the racist comments against Do, which on top of the rise in anti-Asian attacks during the pandemic made people in Orange County’s Little Saigon anxious and angry.

Far from being communists, many of them — including Do — had fled Vietnam to escape communism.

“Coming to a meeting and being passionate about an issue you care about — that’s America. I embrace that every day,” said Supervisor Katrina Foley, one of two Democrats on the five-member panel.

“But coming to a meeting and ... accusing people of being communist traitors — that’s a dog whistle for people to hurt us.”

Leigh Dundas, a lawyer known for fighting against childhood immunization laws, sees it differently.

She has spoken out against mask mandates and digital vaccination records during Board of Supervisors meetings throughout the pandemic, though she has not attended in recent months.

She says those who express similar views believe their freedom is at stake.

The man who lashed out against Do identified himself only as Tyler Durden, the nihilistic lead in the film “Fight Club.”

“It’s less anti-anything and more stay out of our hair and let people make their own decisions on it,” Dundas said.

And it is not just the Board of Supervisors. Over the last year, meetings across Orange County have been increasingly punctuated by antisemitic imagery, conspiracy theories, racism and threats.

In July, because of concerns about violence, Huntington Beach City Council members were escorted by police into a meeting to fill the seat vacated by anti-masker and mixed martial arts fighter Tito Ortiz.

After the council appointed lawyer Rhonda Bolton as its first-ever Black member, people shouted that those who voted in favor were part of the “deep state.”

They yelled that Bolton, who moved to the city about eight years ago, was a “transplant.”

A group called “Save Surf City” immediately started a drive to recall her and other council members.

In Los Alamitos, protesters at school board meetings have decried a new ethnic studies class as “anti-white” and encouraged others to confront school board members at their homes, businesses and churches, according to the Orange County Register.

Calling public officials communists has become a common tactic for those opposed to what they see as infringement on their freedoms in the form of mask mandates, business closures and vaccinations.

Using the term to attack Do — the highest-ranking Vietnamese American elected to political office in Southern California — is particularly fraught, because much of the local Vietnamese community is vehemently anti-communist.

Do, who did not respond to requests for comment, has largely maintained a hands-off approach to protesters during meetings.

When the crowd refuses to calm down, he has sometimes threatened to clear the room.

But he has stopped short of calling on sheriff’s deputies to remove people who are disruptive, something that is permitted under board rules.

“We’ve seen hateful rhetoric in the hall of elected officials at so many levels locally here in Orange County. We cannot let this normalize,” Anti-Defamation League Regional Director Peter Levi said. “Every civic and elected leader must call out the hate, and do everything in their power to ensure it does not escalate even further.”

The previous Orange County public health director, Nichole Quick, resigned in June 2020 after weeks of defending a mask mandate and dealing with protesters who had gathered outside the home she shared with her husband and children.

Chau, her successor, faced protesters outside his Fountain Valley home this summer who accused him of secretly vaccinating children without parental consent.

Another protest at his home, which lasted for two days, included signs that said, “Go back where you came from,” along with placards showing a swastika and an image of him in the guise of Hitler.

When that group first assembled, Chau, who is Vietnamese American, rushed home.

His 85-year-old mother, who lives with him, said not to worry — she had been about to go out and talk to them.

“I am just an American like everybody else,” he said. “For the racists out there, you need to stop it. I have probably contributed to this society more than you have.”

Chau, who often gives presentations about the pandemic at supervisors’ meetings, believes the “aggressive voices” are a minority.

Most residents are following the rules and the science, he said.

“For my own mental health, I don’t engage with them,” said Chau, 56. “These are people who are ignorant, meaning they continue to live in their bubble. They don’t step outside. They’re not aware of what’s going on.”

Once in a while, Chau’s mother, who was imprisoned in Vietnam in the late 1970s after she attempted to flee communism, asks him: “Is it worth it?”

Lisa Bartlett, the first Japanese American elected to the Orange County Board of Supervisors, sees the growing incivility as a manifestation of the frustration and despair that some people have experienced during the pandemic.

“Freedom of speech in all its forms is the hallmark of American liberty,” she said. “But with freedom of speech comes great responsibility. Those racist comments and threats toward anyone’s personal safety are completely unacceptable and highly inappropriate.”

Two weeks after the racist diatribe against Do, the Board of Supervisors met again.

Because of a rise in coronavirus cases, members of the public addressed the board from a nearby room.

As they waited, the group shared debunked theories about the vaccine, including that it contains toxic metals and has sterilized women.

Two men had tattoos associated with the Three Percenters, a far-right militia organization.

During public comment, a woman addressed Do, 58, who came to the U.S. as a boy after the fall of Saigon.

“You are a communist, sir, and I hope you go to jail,” she said.

Do spoke up as the woman walked away from the lectern, underlining what he thought she really meant to say.

“I think the point was to tell me to go back,” he said.