The Centers for Disease Control and Prevention (CDC) has seemingly suppressed vital information regarding the H5N1 bird flu virus under the Trump administration. This week, the New York Times reported that the CDC briefly published, then swiftly removed, data from its Morbidity and Mortality Weekly Report (MMWR) suggesting potential H5N1 transmission between cats and humans.
The retracted data, briefly available in the online MMWR, reportedly included a table detailing a human H5N1 case potentially originating from a pet cat. The CDC has not provided an explanation for the removal or indicated when the report will be republished. A statement currently displayed on the CDC website cites modifications for compliance with President Trump’s Executive Orders. MaagX reached out to the CDC for comment, but received no response at the time of publication.
The Trump administration issued a directive in late January to agencies within the U.S. Department of Health and Human Services (HHS), including the CDC, halting most public communication. While some communication, such as drug safety alerts, continued, the directive interrupted crucial services, notably the CDC’s MMWR, a long-standing weekly publication of studies and case reports.
Leaked memos suggest the administration intended the communication pause to last until February 1. While the MMWR has resumed publication this week, the situation remains far from normal.
Concerning Discrepancies in the MMWR
The February 6 MMWR contains only two reports, both concerning recent wildfires in Los Angeles and Hawaii. Typical MMWRs usually feature significantly more reports, often double or triple this amount (see previous MMWRs published last year). Anonymous health officials previously indicated to the Washington Post that the CDC had three bird flu reports slated for publication before the communication freeze.
H5N1 Transmission Between Cats and Humans: A Growing Concern
The removed table reportedly detailed two H5N1 clusters involving cats. In one instance, a house cat may have infected another cat and a teenager; the initial cat died four days after exhibiting symptoms. The other cluster involved a dairy farmworker potentially transmitting the infection to a cat. The cat became ill two days after the farmworker’s symptoms appeared and died the following day.
H5N1 has been a concern for years, but the risk escalated in early 2024 when a strain crossed the species barrier from birds to dairy cows. Dozens of H5N1 cases have also been reported in cats, which appear more susceptible than cows or humans. While cats can contract the virus from wild birds, some cases link infection to consuming raw milk or farm-sourced food.
The Ongoing Risk of H5N1 and the Importance of Transparency
Health authorities currently consider the risk of H5N1 and other circulating bird flu strains to the public to be low, with limited human-to-human transmission. However, the lack of timely data and information remains deeply troubling. Several concerning developments have emerged since the communication pause.
The USDA recently discovered a novel bird flu strain on a California duck farm originating from an H5N1 outbreak (the ducks were culled in late December, with no further reported cases of this strain). This week, the USDA’s Animal and Plant Health Inspection Service also reported a second type of H5N1 in dairy cows—a type associated with more severe human cases.
The Need for Vigilance and Information Sharing
While these individual incidents are unlikely to trigger a widespread, highly transmissible, and severe H5N1 pandemic, the continued circulation of these viruses in mammals elevates the risk. The ability of the CDC and other agencies to keep the public adequately informed about H5N1 and other emerging public health threats remains uncertain.
