By Betsy McKay and Peter Loftus 

A federal advisory panel declined Wednesday to vote on how Johnson & Johnson's Covid-19 vaccine should be used, saying it needs more time to gather information on the risk of the shot following reports of cases of rare but severe blood clots that developed in a few recipients.

The Advisory Committee on Immunization Practices, or ACIP, said it doesn't have enough information yet about the risk of these unusual side effects to determine whether the vaccine should be continued, discontinued or recommended only for certain groups of the population.

The ACIP expects to meet again in another week or two to revisit the issue. U.S. health officials on Tuesday recommended that use of the J&J vaccine be paused while they investigate.

The ACIP, which advises the Centers for Disease Control and Prevention on vaccination policy, met to review clinical data gathered to date on six women between the ages of 18 and 48 years old who developed clots in vessels draining blood from their brains and in some cases other parts of the body after receiving J&J's vaccine. More than 7.2 million doses of the J&J vaccine have been administered in the U.S.; about 1.5 million of those doses went to women between ages 18 and 50 years.

While Wednesday's discussion was limited to six cases, CDC officials said they expect more will come to light, either cases that have gone unrecognized or that may yet occur. About 52% of the J&J doses to date were administered within the past two weeks.

The ACIP's findings and decisions will help determine how the federal government moves forward with the J&J vaccine at a difficult juncture in the pandemic. The U.S. is racing to vaccinate more people to damp the impact of more infectious and rapidly spreading variants of the Covid-19 virus.

Jeffrey Zients, the White House Covid-19 response coordinator, said Wednesday that supplies of other vaccines are sufficient to make up for scheduled J&J doses and to meet President Biden's goal of reaching 200 million doses in his first 100 days in office. He said 28 million doses of vaccines from Pfizer Inc. and Moderna Inc. were shipped this week.

J&J has said it is aware of the cases involving blood clots and low platelet counts, and is working with health authorities. It is unclear whether the vaccine causes the side effects.

The six cases exceed the background rate for the rare brain blood-clotting condition alone in women of this age group, said Tom Shimabukuro, a vaccine safety expert at the CDC who presented data on the cases. The illness the six women developed -- cerebral venous sinus thrombosis, or CVST, combined with a low-platelet count -- is even more rare, he said.

Based on the current data, J&J believes the overall risk-benefit profile for its vaccine is positive across the population for which it is authorized, Aran Maree, chief medical officer of J&J's pharmaceuticals unit, said during the meeting.

Dr. Maree said J&J was still seeking more details about the six cases since the vaccine was authorized for U.S. use in late February.

The CDC issued an alert to healthcare providers Tuesday warning them to screen patients for the blood-clotting condition who recently received the J&J vaccine and have severe headache or abdominal pain, shortness of breath, backache, leg swelling, new neurological symptoms or new or easy bruising. The condition requires a unique treatment, and healthcare providers shouldn't give these patients the standard treatment, which involves using the anticoagulant heparin, the agency also warned.

The recommendations made by the ACIP's 14 voting members -- medical and public health experts from outside the agency -- go to the CDC director, who decides whether or not to make them policy. The FDA will also review the committee's assessment of the blood-clot cases.

The ACIP recommended who should be prioritized for Covid-19 vaccines, and in which order. After the U.S. Food and Drug Administration authorized Covid-19 vaccines from Pfizer and partner BioNTech, Moderna Inc. and then J&J, the panel recommended the shots.

No obvious risk factors stood out among the six women, the CDC's Dr. Shimabukuro said. All of the patients are white. Whites have received about 64% of the J&J vaccines administered, and men and women ages 18 to 49 years have received 47% of the shots.

One of the women used estrogen or progesterone. None was pregnant or had recently given birth. Three were defined as obese, and one each had hypothyroidism, hypertension, and asthma. None was known to have coagulation disorders, the CDC said.

The patients all initially developed vague symptoms six to 13 days after vaccination. Five had headaches, and one a backache and bruising. Some also had abdominal pain, chills and nausea, and neurological symptoms. All six were diagnosed with blood clots in vessels draining blood from the brain; three also had clots in vessels elsewhere in the body, such as in vessels that drain the intestines.

"We have clots forming in large vessels in the presence of low platelets, " Dr. Shimabukuro said. "It's kind of a paradox here."

One 45 year-old woman died. Three others remain in the hospital, two of whom are intensive care, the CDC said. The remaining two have been discharged from the hospital.

One 48 year-old woman, treated in Omaha, Neb., developed blood clots in vessels in her brain and abdominal cavity two weeks after receiving her vaccine. She was initially treated with heparin, then switched to other medications, and has yet to recover, according to a presentation by Dr. Maree.

Vaccination and infectious disease experts praised the government's quick recommendation to pause the use of J&J's vaccination and then hold an open meeting to evaluate the data.

"It shows that our regulatory agencies are working properly," said Krutika Kuppalli, assistant professor of infectious diseases at the Medical University of South Carolina. "They picked up a signal and they jumped on top of it. They want to be careful; they want to be transparent."

Write to Betsy McKay at and Peter Loftus at


(END) Dow Jones Newswires

April 14, 2021 18:27 ET (22:27 GMT)

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