Remember when you couldn’t get health insurance if you had HIV? Remember when you couldn’t afford your HIV meds even when you had insurance? Those days could return if Congress ultimately succeeds in dismantling the 2010 Affordable Care Act (ACA).

These past few months have seen numerous attempts by the House and the Senate to either repeal the bill entirely or repeal it and replace it with something else. All of the bills proposed thus far dramatically scale back public health insurance for low-income Americans, and eliminate the revenue source for that insurance by cutting taxes—about $33 billion’s worth—for the nation’s 400 wealthiest households.

Here’s why repealing the ACA in full, or replacing it with any of the schemes proposed thus far will put years of healthcare progress at risk. Those impacted the most will be lesbian, gay, bisexual, and transgender (LGBT) people, people living with HIV, and other vulnerable populations that are disproportionately burdened by health disparities and experience barriers to accessing healthcare, such as people of color.

The way that the ACA has made it possible for more than 20 million Americans to get health insurance is by loosening the rules of who can sign up for Medicaid. Medicaid is a public health insurance program that is paid for, in part, by the federal government, but administered by states. Before the ACA became law, Medicaid was restricted to low-income children, pregnant women, parents of dependent children, seniors, and people with disabilities.

But the ACA allows states to offer Medicaid to adults with low annual incomes, even if they have no other qualifying characteristics, such as a disability or responsibility for the care of a child. This change in eligibility has greatly benefitted low-income LGBT adults, many of whom do not have children. It’s also benefitted people living with HIV, who can now sign up for public health insurance while they are still healthy; previously, most states required them to wait until they had become disabled by HIV (by letting it progress to AIDS) to qualify for Medicaid.

These changes have literally saved lives. A study published in the New England Journal of Medicine in 2016 found that making Medicaid available to more people in New York, Arizona, and Maine resulted in a six percent decline in deaths for adults age 20-64. But the study found that the “relative decline in HIV-related mortality was nearly twice as large.” All in all, the study noted, “for every 239 to 316 adults gaining health insurance, one death was prevented each year.”

The potential harm from passage of a Senate bill to replace the ACA would not be limited to people living with HIV, however. Transgender people have some of the highest rates of uninsurance in the country. In 2013, the Center for American Progress found that an astonishing 59% of transgender people who are low income did not have health insurance. By 2017 that number had dropped to 25%. Additionally, after key provisions of the ACA that expanded eligibility for Medicaid went into effect, rates of insurance among lesbian, gay, and bisexual people were cut in half, from 22% to 11%.

One of the other game-changing aspects of the ACA, in addition to expanding Medicaid eligibility, is the elimination of health insurances plans that exist in name only. Today, health insurance plans must provide coverage of essential health benefits, such as prescription drugs, treatment for substance use and behavioral health issues. This is incredibly important for LGBT people as well as people living with HIV, as they have higher rates of depression and anxiety than the general population.

Less well known, but just as important, are the nondiscrimination policies that were enacted by the U.S. Department of Health and Human Services as part of the implementation of the ACA. These new regulations prohibited discrimination against LGBT people, and especially transgender people, in healthcare settings and by insurance companies. Even if the ACA is permitted to stand, the Trump-Pence Administration has signaled its intent to repeal the nondiscrimination rule prohibiting discrimination in health care based on gender identity.

We have long known that LGBT people suffer from greater disparities in health and health outcomes than the general population. We use tobacco, alcohol, and other substances at higher rates than the general population, and experience greater mental health burden. Our young people are more likely to become homeless and they are two to three times more likely to attempt suicide. Our older adults suffer from isolation and a lack of culturally competent care providers. Gay men and transgender people are more vulnerable to HIV and other sexually-transmitted infections. Lesbians are less likely to receive preventive cancer screenings and are more likely to be overweight or obese.

Under the ACA we have been making progress on all of these problems. It’s been slow, but we are moving forward. It’s a safe bet that if Congress repeals or replaces the ACA all of that progress will be at risk.

Remember when you couldn’t get health insurance if you had HIV? Remember when you couldn’t afford your HIV meds even when you had insurance? Those days could return if Congress ultimately succeeds in dismantling the 2010 Affordable Care Act (ACA).

These past few months have seen numerous attempts by the House and the Senate to either repeal the bill entirely or repeal it and replace it with something else. All of the bills proposed thus far dramatically scale back public health insurance for low-income Americans, and eliminate the revenue source for that insurance by cutting taxes—about $33 billion’s worth—for the nation’s 400 wealthiest households.

Here’s why repealing the ACA in full, or replacing it with any of the schemes proposed thus far will put years of healthcare progress at risk. Those impacted the most will be lesbian, gay, bisexual, and transgender (LGBT) people, people living with HIV, and other vulnerable populations that are disproportionately burdened by health disparities and experience barriers to accessing healthcare, such as people of color.

The way that the ACA has made it possible for more than 20 million Americans to get health insurance is by loosening the rules of who can sign up for Medicaid. Medicaid is a public health insurance program that is paid for, in part, by the federal government, but administered by states. Before the ACA became law, Medicaid was restricted to low-income children, pregnant women, parents of dependent children, seniors, and people with disabilities.

But the ACA allows states to offer Medicaid to adults with low annual incomes, even if they have no other qualifying characteristics, such as a disability or responsibility for the care of a child. This change in eligibility has greatly benefitted low-income LGBT adults, many of whom do not have children. It’s also benefitted people living with HIV, who can now sign up for public health insurance while they are still healthy; previously, most states required them to wait until they had become disabled by HIV (by letting it progress to AIDS) to qualify for Medicaid.

These changes have literally saved lives. A study published in the New England Journal of Medicine in 2016 found that making Medicaid available to more people in New York, Arizona, and Maine resulted in a six percent decline in deaths for adults age 20-64. But the study found that the “relative decline in HIV-related mortality was nearly twice as large.” All in all, the study noted, “for every 239 to 316 adults gaining health insurance, one death was prevented each year.”

The potential harm from passage of a Senate bill to replace the ACA would not be limited to people living with HIV, however. Transgender people have some of the highest rates of uninsurance in the country. In 2013, the Center for American Progress found that an astonishing 59% of transgender people who are low income did not have health insurance. By 2017 that number had dropped to 25%. Additionally, after key provisions of the ACA that expanded eligibility for Medicaid went into effect, rates of insurance among lesbian, gay, and bisexual people were cut in half, from 22% to 11%.

One of the other game-changing aspects of the ACA, in addition to expanding Medicaid eligibility, is the elimination of health insurances plans that exist in name only. Today, health insurance plans must provide coverage of essential health benefits, such as prescription drugs, treatment for substance use and behavioral health issues. This is incredibly important for LGBT people as well as people living with HIV, as they have higher rates of depression and anxiety than the general population.

Less well known, but just as important, are the nondiscrimination policies that were enacted by the U.S. Department of Health and Human Services as part of the implementation of the ACA. These new regulations prohibited discrimination against LGBT people, and especially transgender people, in healthcare settings and by insurance companies. Even if the ACA is permitted to stand, the Trump-Pence Administration has signaled its intent to repeal the nondiscrimination rule prohibiting discrimination in health care based on gender identity.

We have long known that LGBT people suffer from greater disparities in health and health outcomes than the general population. We use tobacco, alcohol, and other substances at higher rates than the general population, and experience greater mental health burden. Our young people are more likely to become homeless and they are two to three times more likely to attempt suicide. Our older adults suffer from isolation and a lack of culturally competent care providers. Gay men and transgender people are more vulnerable to HIV and other sexually-transmitted infections. Lesbians are less likely to receive preventive cancer screenings and are more likely to be overweight or obese.

Under the ACA we have been making progress on all of these problems. It’s been slow, but we are moving forward. It’s a safe bet that if Congress repeals or replaces the ACA all of that progress will be at risk.

Tim Wang, MPH, is LGBT Health Policy Analyst for The Fenway Institute at Fenway Health. Sean Cahill, PhD, is Director of Health Policy Research for The Fenway Institute at Fenway Health. They have co-authored two policy briefs on the impact of ACA repeal including, Essential Elements of a Revised National Health Care Policy for LGBT People and People Living with HIV and What the American Health Care Act means for LGBT people and people living with HIV.