Uneven Reporting Raises Doubts About CDC Vaccination Numbers
Data from the Centers for Disease Control and Prevention points to a positive trend: More than 1 million coronavirus vaccine doses on average have been administered everyday for well over a month.
But a closer look at CDC’s vaccine tracker raises questions.
The CDC responded by quietly instituting a cap across the demographic groups they measure that, on paper, prevents any group from exceeding a vaccination rate of 95%. Its tracker now shows that 95% of those 65 and older are at least partially vaccinated instead of 99.9%.
A new footnote explains that the cap “helps address potential overestimates of vaccination coverage due to first, second, and booster doses that were not linked.” It also notes that inaccuracies could arise from part-time residents getting the shots and potential data reporting errors. The agency did not respond to a comment request.
But experts say CDC’s strategy does not solve underlying data issues that could spawn massive miscounts and that it’s important for vaccination coverage data to be accurate so that public health policies can be targeted to where they are most needed.
“We need to know where our vulnerable populations are,” says William Moss, the executive director of the International Vaccine Access Center at the Johns Hopkins Bloomberg School of Public Health. “We need to know where to divert resources. … With variations in data at the state level, it's just very hard to do all that at the federal level or at the national level.”
Discrepancies in CDC, State and County Vaccine Data
Limiting vaccine coverage to 95% in the CDC vaccine tracker doesn’t address the root of the problem, says Howard Forman, a professor of public health at Yale University School of Medicine.
The cap “just says that we're not fools, and we don't think for a minute that it's 100%,” Forman says.
The CDC’s data tracker estimates that more than 56 million Americans ages 65 and older have had at least one shot, while the latest Census Bureau data from 2019 estimates that only 54 million people are even in that age group.
And the agency’s data doesn’t line up with what states and counties are reporting in several cases.
For example, CDC has capped California’s percent of the population aged 65 or older with at least one shot at 95%, but state data shows about 87% of this population has had at least one dose.
CDC has also capped Florida’s 65 and older population at 95% with at least one shot, but the state reports about 90% of the population is at least partially vaccinated.
Based on Census Bureau data on senior citizen populations across the two states, even just a 5% discrepancy would amount to hundreds of thousands of residents in that demographic alone whose vaccination statuses are misidentified.
Both state health departments in statements provided to U.S. News said that CDC has access to additional databases, including vaccine rates from federal facilities, that could change their numbers.
Experts say that part of the problem is the lack of standardization in state reporting.
“I think one place where the United States has really kind of failed is in having standards for state reporting so that we can readily compare numbers across states,” Moss says.
State reporting disparities have been a problem with testing and infection numbers, too, according to Moss.
“There has been such diversity in reporting across states that has made it really difficult to track the pandemic and compare data across states,” Moss says.
County-level data doesn’t always line up, either.
Georgia’s Chattahoochee County appears to be the most vaccinated county in the U.S. – but the number of vaccinated people is four times as large as its population. The real full vaccination rate is 20%, according to the state’s dashboard. A spokesperson from the Georgia Department of Public Health said that the CDC is counting additional vaccinations from the Fort Benning military base.
Similarly, in Portsmouth, Virginia, CDC data shows about 30,000 more fully vaccinated people than the state dashboard. Melissa Gordon, a spokesperson for the Virginia Department of Health, explained that the mistake happened because CDC is counting doses that the Naval Medical Center administered to non-residents.
“CDC is aware of a technical issue impacting some of Virginia’s COVID-19 vaccine administration data. … CDC is working to resolve this issue, and has provided Virginia with the correct data files for the VDH dashboard,” Gordon said.
West Feliciana Parish in Louisiana, home to the state penitentiary, is listed as having a full vaccination rate of 84% in the CDC data, which would put it leagues above the rest of the state. But Louisiana’s own data dashboard indicates that the vaccination rate is 61% as of Monday. In six other Louisiana parishes, the difference between vaccination rates in the state data and the CDC data is 10 percentage points or greater. Mindy Faciane, a spokesperson for the Louisiana Department of Health, could not provide a reason for this discrepancy but noted that “the state dashboard will have the most accurate data.”
This is not to say that the CDC data is always less reliable than state dashboards. Some states don’t count shots from federal sources, which means the CDC’s data is more complete in those cases. For example, Arizona’s dashboard doesn’t count people who got their vaccine from the Indian Health Service, leading to serious undercounting in areas of the state that are part of the Navajo Nation. In this case, the CDC data is more accurate.