Most San Diego County residents are fully vaccinated against COVID-19, but you wouldn’t know it looking at data shared by the Centers for Disease Control and Prevention.
San Diego County health officials reported last Wednesday that 80 percent of San Diegans age 12 and older are fully vaccinated. Almost 90 percent have received at least one dose of the vaccine.
But data from the CDC — whose numbers are widely shared by national news outlets, including the New York Times  — show just over 51 percent  of eligible county residents are fully vaccinated. It reports 99.9 percent of eligible residents have received at least one dose.
A spokeswoman for the CDC this month acknowledged the reporting error in response to a request from Voice of San Diego and pointed to a discrepancy in data shared by the state.
“CDC is aware of an issue in reporting vaccination data from San Diego County, California,” CDC spokeswoman Jasmine Reed wrote in an email. “The county data is submitted to a central aggregator prior to being reported to CDC.”
Reed said states or jurisdictions submit data to a central server where the CDC then collects or analyzes it. She said the CDC is working with the state to update its data, and that issues relating to processing transmission of data occasionally occur. She did not say whether other counties have had the same issue, or why the incorrect numbers have not been removed.
What we know: According to San Diego County health officials, data published on the county vaccination dashboard  is accurate and what’s reported to the state. From there, it’s unclear how the data gets altered.
“Note the number of people the CDC reports with at least a single dose equals nearly the county’s population and exceeds the eligible population,” San Diego County spokeswoman Sarah Sweeney said in an email about the data.
According to the county, 2.8 million residents are currently eligible to receive the vaccine and 2.5 million — or 89.2 percent — have received at least one dose. The CDC reports that 3.4 million county residents have received at least one dose, roughly the county’s entire population.
A spokesperson from the California Department of Public Health said the department continually updates its data to improve data quality, and that updates can include corrections or the deletion of duplicate data after it has been submitted to the CDC.