The U.S. Centers for Disease Control and Preventions director pushed back against a recent Washington Post report that said Trump administration officials were discouraging CDC policy analysts from using the terms diversity, fetus, science-based, vulnerable, evidence-based, transgender and entitlement in documents related to next years budget.

In a tweet, Dr. Brenda Fitzgerald said that there were no banned words at CDC . Subsequent reports by the New York Times do seem to suggest that the request to omit certain words may have been an act of self-censorship on part of the centers. The tactic may have been a way to get their budget passed in a Republican Congress where even the chairman of the House Committee on Science, Space and Technology is a climate change denier .

Unnamed sources in both newspapers assert that the CDCs reported word bans are only for the purposes of budget approvals and wouldnt affect actual research. But the agencys history shows that politicizing science goes hand in hand with restricting research and silencing public health communication, says Dr. Stephanie Zaza, president-elect of the American College of Preventive Medicine and a former medical officer at the CDC for 25 years.

When government agencies and politicians ban or restrict certain scientific and medical terms, the concepts these terms represent then become burdened with political meaning, transforming data and facts into partisan talking points and harmful policies.

For instance, in 1996, the U.S. Congress passed the Dickey Amendment. It states that none of the funds made available for injury prevention and control at the Centers for Disease Control and Prevention may be used to advocate or promote gun control.

In transforming ongoing research about gun ownership and public health into advocacy or gun control promotion, Congress effectively if inadvertently managed to freeze almost all scientific inquiry about the public health effects of gun ownership for two decades.

Language around gun control in the CDCs budget has made it extremely difficult for the CDC to do anything in that arena, even if isnt specifically advocating for gun control, Zaza said. Theyve really had a very hard time finding funding to do things like just surveillance around gun violence.

To date, research on gun violence receives a disproportionately low amount of research funding and results in a disproportionately low number of published studies compared to other causes of death that kill Americans in similar numbers, like motor vehicle collisions or sepsis.

The Helms Amendment also had a similar silencing effect on public health communication. Passed in 1987, it banned the CDC from using federal funds to create HIV/AIDS prevention materials or activities that promote, encourage, and condone homosexual sexual activities or the intravenous use of illegal drugs. In order to comply with the law, the CDC nixed any educational materials with pictures of genital organs, the anus, and either safe or unsafe sex, according to AIDS historian Peter Lewis Allen.

In his book The Wages of Sin: Sex And Disease, Past and Present he writes:

There is no way to know precisely how many Americans died as a result of the Helms amendment and the CDCs content restrictions, but the numbers are likely to have been substantial. Hundred of thousands of Americans were probably infected with HIV between 1988 and 1992. Could effective education have prevented ten percent of those infections? Five percent? Even if only one infection in a hundred could have been averted, the cost of sparing the countrys moral sensibilities ranked in the thousands of lives.

Currently, the majority of Americans hold favorable views of the CDC, but this wont continue if the American public cant rely on it for accurate health information, Zaza said.

If you cant state very clearly and precisely what your budget document means, what your communication to the public means, you can begin to erode the trust, she said. We know that CDC is one of the most trusted U.S. government agencies, and that trust is based not only on its scientific integrity but its ability to communicate scientific information to the public.

The U.S. isnt the only country that struggles with the political censorship of medical terms. Back in 2003, Suruchi Sood was leading an HIV/AIDS prevention campaign in India when she got some startling news. The countrys health minister at the time, Sushma Swaraj, wanted to de-emphasize the word condom in public health efforts to stop the spread of HIV, preferring to focus mainly on abstinence and being faithful.

Instead of the word, condom, Sood said, we had to use the term, protection which effectively dilutes the entire purpose of developing prevention campaigns. At the time, condoms were the only known way to prevent HIV transmission among sexually active people.

The new language was confusing and misleading, Sood said. Health workers didnt know how to discuss safe sex without condoms a serious problem when more than 85 percent of all HIV cases in India at the time were transmitted through sex.

In more authoritarian regimes, especially, the censoring of medical terms can have a rapid detrimental effect on vulnerable populations.

In a tragic and extreme recent example, the New York Times reports that doctors in Venezuela are warned to omit the word malnourishment on childrens medical records, making it difficult to keep track of how many children are dying from starvation. This, in turn, observers say, allows the Venezuelan government to maintain ignorance about the scope of the problem and to reject international aid to help feed its people.

Words Matter! Sood concluded. One of the ways of looking at this is to consider that if you dont have a word for something, does it even exist?