Which diseases
are we closest
to curing?

The full narration of the video.

One pill a day, for two or three months. A liver disease that was once hard to treat: now 95 out of 100 people are rid of it for good. But for most long-term illnesses, medicine is like a bucket under a leak. The bucket matters; you can't remove it for a single day. But the pipe is still leaking.

A cure means fixing the leak and putting the bucket away. Which diseases are closest to that? Let's follow the plumber, house by house. House one is that liver disease: hepatitis C.

A virus moves into the liver, like bugs chewing holes in a pipe. Today's pills wipe the bugs out. Once they're gone, the liver slowly heals itself. A pipe can't do that. A body can.

This house is fixed. The hard part: 47 million people still carry it, and many don't know. House two: sickle cell disease and thalassemia. The trouble is in the blueprint: one wrong letter in the instructions for making blood, so the red cells come out broken.

The fix: take out the little blood factories, correct that letter, and put them back. In 2023, the first letter-editing treatment was approved. This year in Guangxi, China, five thalassemia patients got a Chinese-made edit: all of them stopped needing transfusions.

The catch: before they go back in, strong drugs must clear out the old factories. In the US, it costs over two million dollars. House three: type 1 diabetes. The house's own guards mistake a friend for a burglar and tear out the section that controls blood sugar.

Scientists grew a new section from stem cells and fitted it in. Of twelve patients, ten no longer needed insulin a year later. But the guards are still there, so patients take daily drugs to hold them back. House four: lupus.

This time a squad of guards goes haywire, wrecking everything. Doctors wipe out the whole squad and let the body recruit a new one. The first patients in Germany stopped all their medicines, and most haven't relapsed since.

But the doctors say they'll wait at least five years before calling it a cure. Last house: HIV. This virus hides asleep in the walls; medicine only keeps it from coming out.

About a dozen people worldwide have stopped treatment for years, and the virus never came back. They all had blood cancer and needed a bone marrow transplant. Most donors were born with a rare gene: it locks the virus out. But the transplant itself can kill, so it can't be offered to everyone.

Down the street: hepatitis C is fixed; the blood diseases can be fixed, at a price. Diabetes and lupus are halfway; HIV is still far off. Until the leak is fixed, don't remove your bucket, not even for a day. Of the houses left, which puts its bucket away next: diabetes or lupus?