SAN FRANCISCO (KGO) -- An advisory committee for the Centers for Disease Control and Prevention unanimously decided Wednesday to extend the pause on the Johnson & Johnson COVID-19 vaccine to allow more time to fully review vaccine safety data.
This comes a day after the CDC and the FDA paused any use of the shot while six rare blood clot cases are investigated. Of the six known cases, all the women are white, ranging from 18 to 48 years old. Three of them remain in the hospital. One woman died.
"I think we may be able to work this out within a few days and come back with a hard recommendation like 'we don't give this to women' or 'we don't give this to women under the age of 60,' like the Europeans Medicines Agency has recommended for the AstraZeneca vaccine," said Dr. George Rutherford, UCSF's lead epidemiologist.
The committee discussed the specific risks that apply to women who are more susceptible to the rare blood clot syndrome known as Cerebral Venous Sinus Thrombosis, or CVST.
"Young women are the people who have this condition to begin with," said Dr. Philip Grant, who is currently leading Stanford's Johnson & Johnson clinical trial. "Women are three times more likely to have CVST to begin with."
Grant expects a warning may be issued for women of a specific age group following the CDC's investigation. He says investigators will be looking to see if any of these women had other risk factors for blood clotting, like contraceptives, smoking, or a family risk factor.
"There may be a warning given to women, but still even for most young women it's extremely rare," said Grant.
The CDC confirms one woman was taking birth control and the other three women had pre-existing conditions like obesity, high blood pressure, and asthma. CDC Director Rochelle Walensky expects more cases will be reported.
"We are also not yet certain we have heard about all possible cases as this syndrome may not be easily recognized as one associated with the vaccine," Walensky said during a White House COVID-19 Task Force meeting Wednesday.
Two of the six women had blood clots in their abdominal cavity or the veins in their gastrointestinal tract.
"I think what she's pointing out is for clinicians to be aware of severe abdominal pain," Grant said.
Walensky also said the risk for people who got the Johnson & Johnson vaccine more than a month ago is "exceptionally low."
"For people who have received the vaccine recently, meaning in the last few weeks, they should be aware of their symptoms and immediately seek out any symptoms of concern," said Walensky.
Among the six cases, the most common symptom reported has been headaches. The committee plans to further discuss symptoms and other risk factors in both women and men of all ethnicities.
After reviewing additional data, a final decision from the committee is expected in the coming weeks.
VACCINE TRACKER: How California is doing, when you can get a coronavirus vaccine
Having trouble loading the tracker above? Click here to open it in a new window.
RELATED STORIES & VIDEOS: