In a lab room, a toddler, deaf from birth, sits while a tone plays. There’s no reaction. His face does not change.

Six weeks later, after a single injection of an experimental gene therapy, the same toddler is back in the same room. The tone plays. The toddler’s head turns toward the sound. And somewhere just off screen, the child’s grandfather says his name. The boy turns and looks. He can hear.

“When the parents realized their child had a response to sound they cried,” says Dr. Yilai Shu of the Eye & ENT Hospital of Fudan University, who co-led the trial, in a video that showed the results. “The whole family cried.” The video cuts to another child, thirteen weeks post-treatment, dancing to music.

This is what gene therapy can do in 2026. The clip comes from the international clinical trial of an OTOF gene therapy run by Mass Eye and Ear and China’s Fudan University that provided the underlying science behind a drug the Food and Drug Administration (FDA) approved last week.

On April 23, the FDA granted accelerated approval to Otarmeni, a gene therapy from the pharma company Regeneron for severe-to-profound hearing loss caused by mutations in a gene called OTOF. In a pivotal trial, 80 percent of treated patients gained measurable hearing, and 42 percent reached the level needed to pick up whispers. Two and a half years after treatment, 90 percent of patients in the underlying multi-center trial were still hearing.

It’s a drug that certainly feels like a miracle to those in the trials, taking patients from silence to sound. But what can feel almost as miraculous is how far the broader field of gene therapies like Otarmeni — which deliver a working copy of a broken gene directly into a patient’s cells — have come.

In 1999, the nascent field of gene therapy all but collapsed when a teenager named Jesse Gelsinger died four days after being injected with an experimental gene therapy at the University of Pennsylvania, the first publicly identified death in a gene therapy clinical trial. In the years that followed, funding evaporated, careers ended, and “gene therapy” became a cautionary tale.

It took years and major changes in how gene therapies are delivered for the field to recover. And now, 27 years after Gelsinger’s tragic death, we have a gene therapy that can effectively reverse some kinds of congenital hearing loss. The next decade is no longer about whether gene therapy can deliver clinical results. It’s about whether it can deliver results to enough patients, at prices people can actually pay, for diseases that affect more than a few hundred kids a year.

Get those answers right, and what feels like a miracle to some in 2026 could become ordinary medicine.

After Gelsinger died, the FDA halted gene therapy trials in the US, the National Institutes of Health tightened oversight, and the principal investigator of the Penn study — James Wilson — was barred from clinical trials for five years and stripped of his administrative titles. In the lean years that followed, two things happened.

The first was a change in delivery. Gene therapies use engineered viruses to deliver restorative genes to a patient’s cells. The therapy used on Gelsinger was carried by an adenovirus, which are highly immunogenic, meaning the human immune system recognizes them and reacts violently. It was that immune reaction that killed Gelsinger.

In the aftermath, the field increasingly turned to adeno-associated viruses (AAV), which are smaller, more tolerable, and capable of slipping a payload into the right cells without setting off a five-alarm immune reaction. AAV vectors are now the workhorse of in vivo gene therapy, including in Otarmeni.

The second thing that happened was CRISPR. Adapted in 2012 by Jennifer Doudna and Emmanuelle Charpentier into a precision gene-editing tool, CRISPR could do something AAV could not: find a specific spot in the patient’s own DNA and rewrite the letters there, correcting the broken gene in place. CRISPR also earned gene therapy a cultural moment it hadn’t had since before Gelsinger. Money and talent flooded back into the field — including into the AAV programs that produced Otarmeni.

The clearest sign something has shifted in the field is the lengthening list of therapy approvals. In December 2017, the FDA cleared Luxturna for hereditary blindness from RPE65 mutations — the first gene therapy in the US for an inherited disease. Two years later, Zolgensma was approved for spinal muscular atrophy, a wasting disease that kills children before age two in its severe form. In 2022, Hemgenix made hemophilia B the first bleeding disorder with a one-shot fix. In 2023, Casgevy and Lyfgenia did the same for sickle cell, with Casegevy becoming the first FDA-approved CRISPR therapy.

The sickle cell approvals matter most because they are the first for a patient population that is large; 100,000 Americans suffer from it — mostly Black, and historically underserved. The gene therapies are also proof of concept that the underlying CRISPR mechanism can be redirected at multiple different targets. Verve Therapeutics is using base editing to permanently disable PCSK9, a gene that controls how much LDL cholesterol stays in the bloodstream, with the promise of one-time treatment instead of daily statins for patients at high cardiovascular risk. Early trial data showed a 53 percent average drop in LDL cholesterol. Trials are open for additional hereditary-blindness genes, Pompe disease, and a long list of single-gene conditions.

The science is working, but paying for it is another matter.

While cost may not be a problem for the families that could qualify for Otarmeni, it’s not the only concern. Cochlear implants, the standard treatment for OTOF patients for decades, have been contested within Deaf culture since the 1980s, with many arguing that deafness should be seen as identity rather than deficit. Gene therapy applied to infants makes that question all the more fraught, since the children treated with gene therapy cannot consent to the change. And not everyone would make that choice.

Beyond economic and cultural questions, we lack gene therapy for Alzheimer’s, schizophrenia, or any of the polygenic — meaning, caused by multiple genes — conditions that cause massive amounts of suffering. The cochlear is a good gene-therapy target because it is small and accessible, and OTOF is a single-gene disorder. The brain and Alzheimer’s are neither of those things. The platform that is working in one child’s inner ear in 2026 is not about to deliver universal cures by 2030, or well beyond.

What gene therapies will do, however, is keep filling in the list. The next time a parent gets a rare-disease diagnosis for their child, the question will increasingly be not whether someone is working on a gene therapy, but how soon it will be ready.

A version of this story originally appeared in the Good News newsletter. Sign up here!