[12] Los Angeles-based general practitioner Joel Weisman and immunologist Michael S. Gottlieb of the UCLA Medical Center had encountered a series of gay male patients with symptoms that appeared to be immune system disorders including significant loss of weight and swollen lymph nodes, accompanied by fever and rashes, in addition to two patients with chronic diarrhea, depressed white blood cell counts and fungal infections.

[14] Between 2001 and 2003, various tests showed that the lead content in drinking water in Washington DC more that 10% of the tests were higher than 15 ppb (parts per billion), which was the "action level" fixed by U.S. Environmental Protection Agency (EPA) for stagnant first draw water, and not indicative of typical usage.

On the other hand, the report found some cases of children with BLLs > 5 μg/dL; and also stated that actually "no safe BLL has been identified".

The report later was strongly criticized, by Marc Edwards, some news media, and ultimately by the United States House Committee on Science, Space and Technology.

[18] The results of Marc Edwards et al. came from analysis of the same raw data as those underlying the 2004 CDC report.

In 2007, Edwards wrote to the CDC's associate director of science, James Stephens, questioning the report's conclusions and methodology, and the competence of its principal author.

[18][19] In 2009, the United States House of Representatives' Science and Technology Committee opened a congressional investigation into the 2004 CDC report.

[19] Investigators found that although the CDC and city health department reported dangerous lead levels in 193 children in 2003, the actual number was 486 according to records taken directly from the testing laboratories.

The CDC maintained that the report essentially is correct, but admitted that the presentation was misleading, as regards the absence of data, and as regards the claim that no children with BLLs above the alert threshold 10 μg/dL were found.

That claim, they stated, "was misleading because it referred only to data from the cross-sectional study and did not reflect findings of concern from the separate longitudinal study that showed that children living in homes serviced by a lead water pipe were more than twice as likely as other DC children to have had a blood lead level ≥10 μg/dL".

[20] Starting in June 2020, Michael Caputo, the HHS assistant secretary for public affairs, and his chief advisor Paul Alexander tried to change, delay, suppress, and retroactively edit MMWR stories about the effectiveness of potential treatments for COVID-19, the transmissibility of the virus, and other issues where the president had taken a public stance.

The failure was a direct result of the second Trump administration ordering an indefinite "pause" on public communications by all branches of the U.S. Department of Health and Human Services.

"Preventing CDC from publishing scientific data via the MMWR represents a radical departure from protocol that will undermine the public's trust in the Trump Administration," Jennifer Nuzzo, who runs the Pandemic Center at Brown University, wrote.

[25][26] In the following weeks the administration blocked the release of three studies about the ongoing avian flu outbreak and instead ordered scientists to publish research about the health risks of wildfire.