For over a year, CDC has been collecting data on breakthrough infections, booster shots, and Covid-19 hospitalizations—but hasn't released that data to the public, arguing that it could be misinterpreted, Apoorva Mandavilli reports for the New York Times.

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CDC has withheld Covid-19 data from the public

The Times reports that CDC has published "a tiny fraction" of the Covid-19 data it has collected during the pandemic, according to several people familiar with the agency's data collection practices.

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Last year CDC faced criticism for its decision to track only breakthrough infections that result in hospitalization or death. But according to a federal official familiar with the effort who spoke to the Times, CDC has been collecting this data on Covid-19 vaccines since they were first rolled out, it just chose not to release the numbers for fear of them being misinterpreted as suggesting the vaccines were ineffective.

Kristen Nordlund, a spokesperson for CDC, confirmed to the Times fear of misinterpretation was one reason full breakthrough infection data wasn't released, and added that the data only represents 10% of the U.S. population.

CDC has also been collecting data on Covid-19 hospitalizations broken down by age and race, as well as complete data on the effectiveness of Covid-19 booster shots. But when CDC published the first data on booster shot effectiveness in adults younger than 65 two weeks ago, it excluded data for adults ages 18 to 49.

The agency has also been collecting wastewater data that could provide early signals of an upcoming surge of Covid-19 cases, but only released that data recently, the Times reports.

According to Nordlund, CDC has been slow to release more data "because basically, at the end of the day, it's not yet ready for prime time," adding that CDC's "priority when gathering any data is to ensure that it's accurate and actionable."

Daniel Jernigan, CDC's deputy director of public health science and surveillance, said the pandemic exposed that CDC's data systems, as well as state data systems, are not able to handle large volumes of data. As a result, CDC scientists are working to modernize the systems.

"We want better, faster data that can lead to decision making and actions at all levels of public health, that can help us eliminate the lag in data that has held us back," Jernigan said.

There are also multiple levels of bureaucracy CDC data has to go through before it's publicly released, the Times reports. Multiple divisions must sign off on the data, and CDC officials have to alert HHS and the White House of their plans to release the data.

"The CDC is a political organization as much as it is a public health organization," said Samuel Scarpino, managing director of pathogen surveillance at the Rockefeller Foundation's Pandemic Prevention Institute. "The steps that it takes to get something like this released are often well outside the control of many of the scientists that work at the CDC."

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Health experts surprised CDC withheld data

Some health experts were shocked that CDC has been collecting data but withholding it from the public.

"We have been begging for that sort of granularity of data for two years," said Jessica Malaty Rivera, an epidemiologist and part of the team that ran the Covid Tracking Project. A detailed analysis "builds public trust, and it paints a much clearer picture of what's actually going on," she added.

CDC's reasoning that the data could be misused or misinterpreted wasn't an acceptable reason for withholding it from the public, Rivera said.

"We are at a much greater risk of misinterpreting the data with data vacuums, than sharing the data with proper science, communication, and caveats," she said.

"Tell the truth, present the data," said Paul Offit, a vaccine expert and FDA adviser. "I have to believe that there is a way to explain these things so people can understand it."

Offit added that having more detailed hospitalization data would have been very valuable to the public. To this point, experts have had to rely on booster data from Israel, which hasn't been ideal, as the country defines severe disease differently than the United States, Offit said.

"There's no reason that they should be better at collecting and putting forth data than we were," Offit said. "The CDC is the principal epidemiological agency in this country, and so you would like to think the data came from them."

Pediatric Covid-19 hospitalization data has also been very difficult to acquire to this point, Yvonne Maldonado, chair of the American Academy of Pediatrics' (AAP) Committee on Infections Diseases, said.

A spokesperson for AAP said the group asked CDC for pediatric hospitalization data and was told it wasn't available.

"They've known this for over a year and a half … and they haven't told us," Maldonado said. "I mean, you can't find out anything from them." (Mandavilli, New York Times, 2/20)