The health provider said the potential impact is "not considered significant."
People who received the vaccine at the Kaiser Permanente Walnut Creek Medical Center between October 25 and December 10, 2021 "may have received a slightly less than recommended dose of vaccine."
The amount administered was between 0.01 to 0.04 ml less of the recommended 0.30 ml dose.
That doesn't sound like much, but out of abundance of caution, Kaiser said they immediately consulted infectious disease and vaccine experts in addition to reviewing guidelines from the Centers for Disease Control and Prevention (CDC). All agreed the difference of the amount administered was not significant enough to reduce anyone's protection from the novel coronavirus.
However, anyone affected, who wishes, can repeat the dose as Kaiser is offering special hours and locations for a re-do. They're calling the event an isolated incident.
"We took immediate steps to confirm that the issue was isolated and promptly retrained staff and validated their understanding of the correct procedure. We are continuously monitoring so this does not happen again," a Kaiser statement read.