The Centers for Disease Control and Prevention on Thursday recommended Pfizer’s and Moderna’s vaccines over Johnson & Johnson’s shot for adults, after finding dozens of people developed a rare blood clot condition following vaccination with J&J shots. All of those patients were hospitalized, and nine died.

The CDC has confirmed 54 cases of people developing blood clots and showing low blood platelet levels — a new condition called thrombosis with thrombocytopenia syndrome, or TTS, which mostly affects younger women. Of those cases, 36 required treatment in intensive care.

In a statement Thursday evening, the CDC said the U.S. has an abundant supply of Pfizer and Moderna vaccines. The agency emphasized that people who are unwilling or unable to receive Pfizer and Moderna shots will still have access to the J&J vaccine.

The CDC’s expert vaccine panel, the Advisory Committee on Immunization Practices, voted unanimously in favor of the recommendation earlier Thursday. Hours later, CDC Director Rochelle Walensky gave her endorsement.

“Today’s updated recommendation emphasizes CDC’s commitment to provide real-time scientific information to the American public,” Walensky said.

The U.S. has administered more than 17 million J&J doses since the Food and Drug Administration authorized the shot on an emergency basis in February. Overall, 3.8 TTS cases were reported per million doses administered, according to the CDC. The rates were highest among women 30 to 49 years old.

Panel experts said the J&J shot may still make sense for people who would have allergic reactions to the Pfizer or Moderna vaccines, or if a patient doesn’t have access to any other shot.

However, the CDC recommendation delivers another blow to confidence in Johnson & Johnson’s vaccine. The U.S. briefly paused administration of the shots in April when TTS cases first started emerging.

“The TTS case reporting rates following Janssen vaccines is higher than previous estimates in men as well as women in a wider age range,” Dr. Keipp Talbot, chair of the CDC’s vaccine and safety subgroup, told the advisory panel. Janssen is J&J’s vaccines division.

Seven of the patients who died were women and two were men, with a median age of 45. Most of the people who died had underlying health conditions such as obesity, hypertension and diabetes. The death reporting rate was 0.57 fatalities per million doses administered, according to the CDC.

“We’ve been struck on reviewing these cases by how rapidly patient status deteriorates and results in death,” Dr. Isaac See of the CDC’s vaccine safety team told the advisory panel.

Patients typically developed symptoms nine days after vaccination and were hospitalized five days after they developed symptoms, according to the CDC. The overwhelming majority of patients were women, 37 total, and the median age was 44. Seventeen men developed TTS.

Johnson & Johnson’s Penny Heaton, global therapeutics area head for vaccines, defended the company’s shot during the meeting, saying it “is saving lives here in the USA and on every continent around the globe.”

“It’s easy to store and transport,” Heaton said. “In many low- and middle-income countries, our vaccine is the most important and sometimes the only option. Even in the U.S., given its durable protection it may be the preferred choice for people who can’t or won’t return for multiple vaccinations.”

Heaton said J&J recognizes the incidents of TTS associated with the vaccine and that the condition can be fatal, though the cases are rare. She said patient safety and well-being remains J&J’s top priority and that the company has several studies underway to identify risk factors associated with the development of TTS.

Though the CDC panel’s recommendation was unanimous, some members grappled with the vote. The vaccine experts also could have recommended pulling the shot altogether or limiting it to certain age or demographic groups.

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Dr. Pablo Sanchez, a professor of pediatrics at Ohio State University, said he is not recommending the J&J shot for any of his patients, though he ultimately voted for the panel’s motion.

“I just cannot recommend a vaccine that is associated with a condition that may lead to death,” Sanchez told the committee. “I am not recommending it to any of my patients’ parents.”

However, members also had to weigh the full risks and benefits of their recommendation. Limiting the J&J vaccine to adults 50 and older, for example, would remove the shot as an option for young men who are at risk of developing a rare heart condition called myocarditis associated with the Pfizer and Moderna shots.

And pulling the J&J vaccine altogether could deliver a blow to the shot worldwide. J&J has said the vaccine is easier to distribute to hard-to-reach communities not just in the U.S. but around the world because it is a single dose, reducing logistical hurdles compared with the two-dose vaccines.

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“I believe that we should really keep in mind that our decision does or likely will have a global impact,” said Dr. Oliver Brooks, the chief medical officer at Watts Healthcare in California.

In April, the FDA and the CDC briefly halted the use of Johnson & Johnson’s single-shot vaccine, after six adult women developed blood clots and low blood platelet levels at the same time.

A week later, the FDA and the CDC lifted the pause on J&J shots after the independent advisory panel said the benefits of the shots outweighed the risks. The panel at the time did not recommend restricting the shots by age or gender. It did propose that the FDA add a warning label for women younger than 50.

The FDA has told health-care providers that they shouldn’t administer a J&J booster to people who have a history of developing TTS after the first shot. The FDA also said the J&J shot should not be administered to people who received AstraZeneca’s vaccine, though AstraZeneca is not authorized for use in the U.S.

CDC experts on Thursday said no TTS cases have been identified in people who have received J&J booster doses, though the number of boosters is relatively small.

“Currently available evidence supports a causal relationship between TTS and the Janssen COVID-19 Vaccine,” the FDA said in the fact sheet for health-care providers.

In October, the FDA and CDC authorized J&J boosters for all adults at least two months after their initial J&J shot. More than 800,000 people have received J&J boosters, according to CDC data. People who received their primary vaccination with the J&J shot can also get their booster with a Pfizer or Moderna vaccine.