As police handcuffed two men in doctor’s coats and scrubs who were lying on the ground in protest of the government’s refusal to offer vaccinations to migrants held in detention, protesters gathered this week in front of U.S. Customs and Border Protection headquarters in San Diego sang in a chorus of constant chants.

“No more deaths! No más muertes!”

“Shame! Shame! Shame!”

“Which side are you on? Which side are you on?”

Sparked by the deaths of three migrant children in the last year due to complications from the flu while in federal custody, the three-day protest attracted left-leaning immigration activists and volunteer doctors, including four other demonstrators who were arrested on Tuesday, who offered to help vaccinate willing detainees for the winter.

The display from medical professionals irked by the Trump administration’s position ended on Wednesday after Border Patrol officials in San Diego told Bonnie Arzuaga and other protest leaders that they would pass along the request to offer free vaccines to detained migrants. The federal immigration officials forwarded the group’s letter to the agency’s chief medical officer, Arzuaga said, and told the doctors to expect a follow-up phone call later this week.

“I’ve never had to fight so hard to give a vaccination to anyone, any patient, any population of patients who have needed it the most,” Arzuaga, a Boston-based pediatrician of 11 years, told The Washington Post early Thursday. “As a physician, I’m saddened by the stance our government has taken to deny basic preventative medicine to the people it is holding in its custody.”

The protests this week reflect growing tensions under the Trump administration between federal immigration officials and medical experts who believe migrants are being denied lifesaving preventive medicine while held in federal detention centers.

Even with the assurance that the doctors’ push for free vaccinations would be considered, federal officials have already mocked the medical professionals, belittling them publicly and equating administering vaccines to injecting drugs.

“Of course Border Patrol isn’t going to let a random group of radical political activists show up and start injecting people with drugs,” the Department of Homeland Security’s press secretary tweeted this week.

In a statement, CBP told The Post that the agency has never vaccinated migrants held in its custody, in part because most people will either be released or transferred to another federal agency within 72 hours of entering a Border Patrol facility. Long-term detention centers run by Immigration and Customs Enforcement and the Department of Health and Human Services do vaccinate immigrants housed in their facilities.

“It has never been a CBP practice to administer vaccines and this not a new policy,” an agency spokeswoman said. “We would encourage those who wish to volunteer medical services to go to shelters and NGO facilities, both in the U.S. and in Mexico, to donate their time and services.”

The agency’s policy is complicated by increasingly congested detention centers, which have been struggling to process entering migrants within that 72-hour window. By the agency’s own admission, it has held people beyond that window, including hundreds of children who have been held for an average of six days, twice the legally allowed time.

Doctors at Johns Hopkins and Harvard urged Congress in August to investigate unsanitary conditions inside CBP facilities, which they said could lead to outbreaks of deadly, infectious diseases. They were particularly concerned about the flu.

“Poor conditions at the facilities may be amplifying the spread of influenza and other infectious diseases, increasing health risks to children,” they wrote in a letter to Congress.

Outcry over conditions inside Border Patrol facilities reignited last month after a letter written by officials within the Centers for Disease Control and Prevention became public. The infectious disease experts urged CBP to adopt several new practices to protect the health of people in the agency’s custody, but one notable suggestion went ignored: offering flu vaccines.

Despite refusing to offer flu shots, a CBP spokeswoman told The Post that the federal agency did adopt the CDC’s recommendation to hire more nurses and physicians assistants, increasing its medical personnel from about 20 just over a year ago to 250 on staff now.

Criticism of conditions within CBP facilities was renewed last week, when ProPublica published video of a 16-year-old Guatemalan boy who died in the agency’s custody in May after being left alone for hours, even though both he and another child sharing his cell were seriously ill. The teenager, Carlos Gregorio Hernandez Vasquez, had been diagnosed with the flu.

Five other children have died while in U.S. custody in the past year, including two others who had been diagnosed with the flu, following nearly a decade in which federal officials reported no juvenile deaths.

The protesting doctors, who call themselves Doctors for Camp Closure, showed up at the CBP headquarters in San Diego on Monday with their medical licenses and supplies to inoculate at least 100 people against the flu. But they were unsuccessful, with Border Patrol officials turning them away.

“This is intentional cruelty,” Marie DeLuca, an emergency medicine research fellow from New York, said in a statement. “People are needlessly suffering and dying. You can’t lock people up in inhumane conditions, watch them get sick, and then refuse them access to medical care.”