Roughly 6,300 people who got vaccinated at the Oakland Coliseum COVID-19 vaccination site last week "may have received slightly less than the recommended dose" of Pfizer's vaccine, but not to the point where a redo shot is needed, the California Department of Public Health (CDPH) said Monday.
The underdosing issue happened on Feb. 28 after 4:30 p.m. and on March 1 between 8 a.m. and 3 p.m., according to CDPH.
"While the recommended dose of the Pfizer COVID-19 vaccine is 0.3 ml, the CDC has determined that any dosage of 0.15 ml or larger is safe and does not require the dose to be repeated to protect people against COVID-19," CDPH said in a statement. "In this instance, some individuals may have received a dose of 0.22 ml, which is well within the range outlined by the CDC."
CDPH said the issue was corrected by staff on the afternoon of March 1 and added it "has implemented additional training and quality assurance steps as a preventative measure."
CDPH said it was sending a letter to the people who may have been impacted.
"Right now it’s unfortunate people are uncertain and people are putting trust in the hands of individuals that need to make certain that those proper doses are met," said Howard Butler, who works in the health care field.
The California Governor's Office of Emergency Services (Cal OES) first told NBC Bay Area that the agency wasn't aware of the problem, but by Monday night, they changed their tune.
"Based on what they knew at that time there was no indication that there was any concern around the smaller amounts of dosing that actually occurred," said Dr. Tomas Aragon, Cal OES director.
CDPH did a follow up investigation on site.
"There was a new lot of syringe lots that came in the workers adjusted the amount they were putting in the syringe and it turns out they were putting in slightly lesser amounts that should have been put in," said Aragon. "People do not have to repeat their dose. That is the most important message to get out. We do need for them to come back and get their second dose."
UCSF Infectious Disease Expert Dr. George Rutherford said the amount of vaccine people got and the amount they were supposed to get are about the same.