Six months after the passage of health care reform, the bill became a little more real for millions of Americans. Today, a set of key components of the Patient Protection and Affordable Care Act went into effect, and it’s big news for hundreds of thousands of people who’ve either been kicked off of their insurance, or prevented from getting it altogether. But as the GOP mounts an aggressive attack campaign, advocates worry that society’s most vulnerable are still left out in the cold.

There are four important changes to keep an eye on. First, it’s now much harder for insurance companies to deny or terminate coverage to sick people. Second, the new rules allow young adults to remain on their parent’s health insurance plans through the age of 26. Medicare recipients can also now use their coverage to pay for expensive medications, and lastly, private insurers are required to cover a broader swath of preventative services.

As Karen Davis writes for the Huffington Post, today’s changes mark a significant step forward in the four-year process of implementing the new health care bill. But the reform process is far from over.

Today, as part of their new Pledge to America, the GOP vowed to rollback the President’s signature health care reform bill if they gain control of Congress after November. And as these threats mount, advocates are gearing up to ensure the bill is not gutted.

Eesha Pandit, Director of Advocacy at MergerWatch, says, "we have to make sure that the most vulnerable members of our society actually get access to health coverage they can afford."

Pandit explains that there is a still a fight to ensure that abortion coverage is available. And, she adds, "in the coming years each state will create an insurance exchange, and we have to make sure that health coverage in the exchanges is affordable."

And, beyond affordability, there remain serious questions about access. "There’s going to be a major expansion of Medicaid," explains Pandit, "and we have to make sure there are enough doctors and nurses and community heath centers to treat people."

Community health clinics, which have received billions of dollars in aid from the health care bill, may be one of the few places where those who lack access to health coverage can access care. Clinics function as safety net providers, and when people really need health care, that’s where they go. 

But if the GOP gains control of Congress, even these provisions may be in danger, along with three and half years worth of future changes.

Despite the broad expansions that the Patient Protection and Affordable Care Act will usher in, there are some who were explicitly excluded from coverage. "Undocumented immigrants are completely excluded from the bill," says Pandit. "These Clinics will be important points of access to health care for them. It’s important that we fight to make sure they’re fully funded, meaning that the money promised to strengthen and expand the network of CHC’s actually gets out to them."

Regardless of what happens in November, ensuring that health care funding goes to those most in need will continue to be a battle. Advocates say they’re waging it.