The Centers for Disease Control and Prevention and Food and Drug Administration have lifted a 10-day pause on the Johnson & Johnson vaccine, but will issue a fact sheet to medical providers warning them of the potential for extremely rare but serious blood clots.
There will be little delay in the J&J one-dose shots being offered again, officials said.
Dr. Peter Marks, director of FDA's Center for Biologics Evaluation and Research, said shots should be able to resume "shortly after this announcement. ... I would expect them to resume probably by tomorrow morning, even."
Marks said the FDA had been prepping revised fact sheets over the past few days in advance for both providers and patients.
"Those fact sheets are now actually approved, and out there," he said. "That's the beautiful thing about the electronic world and printing on demand."
Earlier in the day, citing an urgent need to vaccinate the country, a government advisory panel had recommended that the nation resume injections of the J&J vaccine.
CDC Director Dr. Rochelle Walensky, voiced her support for lifting the pause and announced she had already signed the Advisory Committee on Immunization Practices' recommendation.
"Above all else, your health and safety come first," Walensky said. "We at the CDC and FDA took the time needed to fully investigate this issue. ... The pause of this vaccine allowed us to ensure that the health care providers and additional patients were treated appropriately."
The panel, which advises the CDC, voted 10-4 with one abstaining to move forward. Panel members voting against the plan wanted a more specific warning to women, who appeared to be more vulnerable to the blood clots. But others said they didn't want any specific warning to women to deter them from getting vaccinated because this type of clotting was so rare.
"Removing a vaccine that can be given as a single dose and is a preference among Latinos in our communities would be a detriment," said Dr. Jose Romero, chair of the panel and the director of Arkansas Health Department.
There are now 15 confirmed reports of a rare condition that includes blood clots with low platelet counts following the J&J vaccine, with a dozen of the clots occurring in veins near the surface of the brain, a condition called “cerebral venous sinus thrombosis,” according to the CDC.
That’s more than double the cases initially reported that prompted federal regulators to recommend a temporary suspension.
Experts caution the reactions are rare. The 15 cases are out of the nearly 8 million J&J shots given. But women under age 50 also seem to be significantly more vulnerable to these abnormal reactions.
Dr. Tom Shimabukuro, a member of the CDC’s task force on COVID-19 vaccines, told the panel that all of the 15 cases were women. Most of them were in their 30s, although the age range was 18 to 59. Three of the women died.
J&J said it would continue to work with the CDC and federal regulators "to ensure this very rare event can be identified early and treated effectively. We remain committed to the health and safety of people worldwide."
Dr. Francis Collins, director of the National Institutes of Health, said earlier in the day that he was ready to see J&J vaccinations resume.
“I think it is important to point out that this is a treatable condition if you recognize it right away," Collins said.
In debating how to move forward, the panel declined to include a specific warning to women under 50 not to take the vaccine. Several members expressed concern that doing so could deter women from getting vaccinated at all.
Dr. Jason Goldman, a liaison representative to the panel, said he favors allowing the vaccine to move forward with a more general warning that can’t be misinterpreted.
"I’m a firm believer that the perfect should never be the enemy of the good. I think the risks and benefits of this vaccine clearly show that we're preventing tremendous disease," Goldman said.
Members also dismissed the idea of restricting the vaccine to men only.
"In a time when we're trying to vaccinate as many folks as possible in any given period of hours, it might slow things down, even a couple of percentage points may have an impact," said Dr. Nirav Shah, director of the Maine Center for Disease Control and Prevention.
Instead, the panel agreed to recommend the vaccine as authorized by the Food and Drug Administration. As part of that plan, the FDA would provide fact sheets for health care professionals and recipients that detail the risks involved and give guidelines for treatment.
Following the vote, several members said they remain concerned that the public won’t necessarily read the fact sheets. Dr. Beth Bell, a member of the panel, voted in favor of the move but said it’s up to the CDC and other public health officials to educate the public.
"I am concerned that ... women in this age group in particular will not be adequately informed just by the FDA," Bell said.
"We really are depending on the public health agencies and the partner organizations to make sure that people actually are informed and are empowered, and that they actually get a balanced perspective," Dr. Bell said.
Mathai Mammen, global head of research and development at J&J’s Janssen Pharmaceuticals, warned that limiting availability of the vaccine would hurt the world’s chances of achieving "herd immunity."
In an emergency meeting last week, members of the advisory panel said they had too little data to make a recommendation either way, including whether younger women were more at risk. The advisers said they wanted to see if more cases emerged from the estimated 3 million people who received that vaccine in recent weeks before making a decision.
The disruption came at a critical time of the pandemic, with death and hospitalization rates tied to COVID-19 on the rise in nearly half the country. Health experts warned that variants of the virus were spreading more easily, impacting younger patients and that it's critical to vaccinate the broader population quickly before new variants might take hold.
At the same time, federal regulators wanted to alert doctors and hospitals to be on the lookout for complications and to know how to treat them. Heparin, a commonly used blood thinner, appeared to worsen conditions.
ABC News' Arielle Mitropoulos and Sony Salzman contributed to this report.