Los Angeles clinic diluted more than 2,000 doses of COVID vaccine

Clínica Romero medical staff walk to the area where the COVID-19 vaccine was being given to patients.
Clínica Romero medical staff in Los Angeles walk to the area where the COVID-19 vaccine was being given to patients in February 2021.
(Genaro Molina / Los Angeles Times)

The chief executive of a Los Angeles County community health center apologized this week after it came to light that it had administered more than 2,000 diluted doses of the Pfizer-BioNTech COVID-19 vaccine last year.

The incident, first reported by L.A. Taco, was confirmed by the Los Angeles County Department of Public Health and Clínica Romero, the federally qualified health center where the mix-up took place.

“We were in contact immediately and we communicated with everybody and, at this point, we haven’t had any patients with any problems,” Carlos Vaquerano, Clínica Romero’s chief executive, said in an interview Friday. “We understand their concern and I apologize for what happened.”

Diluted doses were administered at Clínica Romero’s locations in Boyle Heights and Westlake and roughly 2,100 people were affected, according to county health officials. Vaquerano said the shots were given out around September and October of last year.


However, Vaquerano said his organization didn’t learn what had happened until May.

The issue, he said, stemmed from a staff member who continued diluting doses of the Pfizer-BioNTech vaccine when doing so was no longer required — resulting in a less-potent formulation.

The employee in question was placed on leave and eventually fired.

After learning of the issue, Vaquerano said Clínica Romero notified public health authorities, as well as Pfizer and the U.S. Centers for Disease Control and Prevention.

In a statement, the L.A. County Department of Public Health said it first learned of the problem June 8.

“Nursing staff reached out to the provider that same day to determine what happened and confirmed that errors in diluting the vaccine occurred at two different sites,” the Department of Public Health said in a statement. “DPH staff confirmed that the clinic had identified the problem and had already take steps to correct the issues.”

Five days later, health department officials conducted site visits at both locations.

“The issues were addressed with the medical director, the vaccine coordinator and their clinical team. No other issues were identified during the visits,” according to the department.

Since it was not clear if the initial shots included enough of the dose to protect against the virus, Department of Public Health nurses advised the clinic to re-administer the injections.


If a lower-than-authorized dose is administered, the CDC says patients should get a repeat dose promptly — though some experts recommend delaying the repeat dose for eight weeks.

Dr. Robert Kim-Farley, an epidemiologist and infectious-diseases expert at the UCLA Fielding School of Public Health, said getting a lower-than-expected vaccine dose could mean the shot administered might be “less effective for preventing infection … and less effective in preventing severe disease.”

Clínica Romero submitted an action plan June 14 to the Department of Public Health to address the issue.

Officials said they would set up an 800 telephone line to answer questions for patients about the issue and also set up special clinics for those who received the diluted doses.

Public Health “remained in contact with the provider as they disseminated letters to affected individuals and completed their action plan,” the statement said.

Vaquerano said affected patients have been informed that they can get another dose but could not say how many have done so to this point.

“It’s a human mistake and we are sorry for that,” he said. “But what I can tell you is that we will continue to work with our community. We have done what it being recommended by the Department of Public Health and we are in touch with them and Pfizer and CDC and doing what is supposed to be done.”

One man who received his booster vaccine from Clínica Romero in October 2021 was shocked when he received the clinic’s response letter in August.

“Dear Valued Patient … Clinica Romero has been made aware that we may have diluted the Pfizer COVID-19 vaccines,” read the letter, according to L.A. Taco.

It informed him that his vaccine had a “lower than recommended” dose and that he should get another.

“I open it, and I’m like, what the hell?” Pedro said in an interview with the news outlet. The article did not include his last name and did not give a reason why.

“How am I getting this letter dated August 1st telling me they immediately corrected a situation that happened in October?” he added.

Clínica Romero has historically served a largely immigrant population, founded in 1983 by Salvadoran immigrants to be a resource for Central American war refugees.

Its mission is to provide services for the “uninsured, insured and underserved.”

The clinic faced off with the county in 2021, when it received only 100 doses of the COVID-19 vaccine despite having 12,000 patients.

“How is 100 going to take care of the 12,000 patients and the surrounding community of 1 million?” asked Dr. Don Garcia, the clinic’s medical director. “This is embarrassing.”

Despite this issue, Vaquerano said he’s confident Clínica Romero retains the trust of the communities it serves.

“I invite them to look at our record,” he said, adding, “we will continue doing our job because our job is to serve with compassion, serving the underserved.”

Times staff writer Rong-Gong Lin II contributed to this report.