Ever since Alzheimer’s disease was first identified 120 years ago, it’s been associated with helplessness. It was hard to diagnose conclusively, and even if it was, there was nothing anyone could do about it. If a loved one had it—as my father did—you just had to watch them slowly disappear.

But thanks to recent scientific breakthroughs in diagnosing and treating Alzheimer’s, we’re not helpless anymore. I have been funding research on it since 2017, and although these new tools are not perfect, they are far and away the best news about this disease I have ever seen.

Now the field is running into a different challenge: The innovations aren’t reaching everyone who needs them. As I heard from a group of Alzheimer’s experts when we got together this past weekend, the scientific breakthroughs have outpaced the system designed to deliver them to doctors and patients. Fixing this problem is the next big frontier in Alzheimer’s.

The breakthroughs: a simple blood test for Alzheimer’s, and treatment if you need it.

It used to be that the only way to diagnose Alzheimer’s was with an expensive brain scan or spinal tap. That hurdle created a vicious cycle. Few people got tested because the procedure was so burdensome, and there was no treatment available anyway. Without large groups of people who were definitively diagnosed, researchers struggled to find patients who were eligible for clinical trials of tests and treatments. That inhibited the research that would lead to new tools, keeping the field largely stagnant for decades.

That is why the recent development of blood tests is such a big breakthrough. For the patient, the experience is the same as getting blood drawn to check your cholesterol. The first two blood tests came out last year, and the U.S. FDA just approved two new ones in August.

On treatment, the FDA has approved two antibody therapies that clear amyloid, the protein that is strongly associated with Alzheimer’s, and modestly slow cognitive decline. Both involve going to a clinic for an infusion, a process similar to the way cancer patients get chemotherapy.

The latest innovation happened just earlier this year: In July, the FDA approved a version that you can take at home with an injectable pen, the same thing that people use to take their GLP-1s. This makes it a lot more practical for patients, especially elderly people who are homebound or have limited mobility.

In the United States, Medicare even pays for the infusion treatment, making it more affordable for patients.

Why aren’t more people taking advantage of them?

The Alzheimer’s experts I met with over the weekend were in Seattle for a medical conference. When I asked them what uptake on these tools has been like, the consensus around the table was clear: It has been slow.

I was surprised to hear that, but not shocked. Most of my work is in global health, on diseases that disproportionately affect the poorest people in the world. Often—with vaccines, for example—there’s a solution that is widely available in high-income countries but unaffordable or impractical in low-income ones. A big part of the Gates Foundation’s mission is to close that delivery gap so everyone benefits from scientific innovations.

So what the Alzheimer’s specialists were telling me felt familiar. It’s not enough to make scientific breakthroughs; we also need breakthroughs in the systems that deliver them to patients. Here are some of the barriers we talked about:

1. Not everyone is aware. According to the experts I spoke with, many doctors and patients simply don’t know that these tests and treatments are available.
2. It can take months to be approved for treatment. Primary care doctors are able to order the blood tests, but typically only memory specialists prescribe treatment. Since it can take months to get an appointment with a specialist, patients with a positive diagnosis often face a long wait before they can start their medication. That lost time is precious because the earlier you start treatment, the more effective it is.
3. There are regulatory and bureaucratic obstacles. Most countries other than the U.S. don’t cover the blood tests in their health plans. Even in the U.S., whether Medicare will pay to test you depends on where you live. It doesn’t cover screening for cognitively healthy people at all. And patients have to pay much more out of pocket for the new injectable treatment than for the infusion.
4. The infusion treatments are burdensome and have side effects. One of the drugs requires getting to an infusion clinic every two weeks for a year and a half, and then monthly after that. For a lot of patients, that is more than they can manage. In addition, the medicines can cause significant side effects in rare cases, so patients have to get a series of MRIs in the early stages of treatment.
5. Clinical trials still struggle to find volunteers. To enroll, you have to live near a site where the trial is being run and be able to travel there. Researchers have an especially hard time recruiting diverse groups of participants, so they don’t understand the benefits of treatment equally across ethnic and racial groups.

What’s next?

I am thinking about how we can lower these barriers to delivery. Ultimately there should be an ecosystem of companies and providers working together. I don’t yet know what my role might be, but I am looking for ways to bring the right partners together to get things going.

One concrete thing that will accelerate progress is to get more people volunteering for clinical trials. The Alzheimer’s Association has an online tool that helps you learn whether you or a loved one is eligible and find an appropriate study if you are.

In the meantime, I am excited about the advances that are still to come. New blood tests are being developed that would detect tau, the protein that kills neurons and causes cognitive decline. New drugs could attack tau as well.

On the prevention side, published studies have already shown that diet, exercise, and social interactions can reduce the risk of cognitive decline; now researchers are studying whether treating people before they start showing symptoms will slow down the progression of the disease, delay its onset, or even prevent it altogether.

All of this work has implications for the entire world. Life spans are going up nearly everywhere, and people deserve to enjoy their golden years. I am optimistic that science will give us the tools to defeat Alzheimer’s. Let’s make sure those tools reach everyone who will need them.