Vaccine advisers to the Centers for Disease Control and Prevention meet Friday to make recommendations for use of the Johnson & Johnson Covid-19 vaccine after it was put on hold to investigate a potential link to serious blood clots.
The CDC and US Food and Drug Administration recommended a pause on use of the J&J coronavirus vaccine last week following six reported US cases of a rare and severe type of blood clot.
They are investigating whether there are more cases and whether other types of blood clots might be associated with the vaccine. The pause was also intended to give experts time to inform doctors about how to look for and treat these clots.
The CDC's Advisory Committee on Immunization Practices met on April 14, but members said they needed more information about the J&J vaccine and the blood clot cases.
Dr. William Schaffner, a non-voting ACIP member and infectious diseases professor at the Vanderbilt University School of Medicine, told CNN that the committee delayed making a decision because there will likely be more reports of blood clots connected to the vaccine, and members need to understand the demographics of those cases.
Schaffner said Friday's meeting could play out a few different ways.
ACIP could recommend that use of the vaccine resume with no changes, or the committee could recommend that the US stop using the J&J vaccine altogether.
Schaffner said it's more likely that ACIP will recommend that use of the vaccine resume with a warning about possible adverse effects -- and potentially, advice to the highest-risk populations to steer clear of this vaccine altogether.
ACIP chair Dr. Jose Romero told CNN that the committee also has the option to recommend the pause continue until more information is gathered -- though he believes enough data has been generated at this point for ACIP to make a decision.
Romero said he has yet to examine the data that will be considered Friday but does not believe the committee will decide to recommend a complete stop to use of the vaccine in the US.
"CDC scientists can make an estimate of what the benefit-risk analysis would be, and that's certainly going to inform us in our decision," said Romero. "Whoever uses the vaccine -- as with any vaccine in this country -- they should be informed about any risks associated with it."
He noted that a potential Covid-19 vaccine booster dose may eventually need to be considered.
"If there's a high-risk population that is indicated that they should not receive the vaccine, then I would imagine the CDC will make recommendations about what the alternative vaccine would be in that group," Romero said.
What action could ACIP take?
One blood clot case in a 25-year-old man was reported during the vaccine's clinical trial. Though the six cases that led to the pause last week were all among women between the ages of 18 and 48, Schaffner said that may not be an accurate representation of risk.
Nearly 8 million people in the US have now received the J&J vaccine. Doctors could realize now that cases of these rare blood clots that they've recently seen were connected to the vaccine, and new cases could emerge among people who have received the vaccine in recent weeks.
"Some of the ACIP members are concerned that this additional reporting may show cases of men or older persons, who are currently not represented in the reporting of the six cases, and so they didn't think the entire picture of risk has been developed," said Schaffner.
CDC Director Dr. Rochelle Walensky said Monday that the agency is now looking through a handful of reported adverse events after use of the J&J vaccine.
Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, said Sunday that he expects the vaccine to come back on the market with restrictions or warnings after Friday's meeting.
J&J Chief Scientific Officer Dr. Paul Stoffels said Tuesday the company believes the benefits of the vaccine outweigh the risks.
"The safety and well-being of the people who use our product is our number one priority and we strongly support awareness of the signs and symptoms of this extremely rare event to ensure the correct diagnosis, appropriate treatment and expedited report by health care professionals," Stoffels said.
Romero, who also serves as Arkansas' secretary of health, said there could be additional recommendations for states and physicians around how to manage J&J doses that have already been distributed. He said he believes states will accept the committee's recommendations.
"My counsel to the governor as we go forward will be, 'Let's see what the CDC says,'" said Romero. "More than likely -- I mean more than 98% -- I'm going to say I agree with the recommendations issued by the committee, and those are the ones we should follow in our state."
Though there is some concern that the J&J vaccine pause will fuel vaccine hesitancy, an Axios-Ipsos poll published Tuesday showed that 88% of Americans think the CDC and FDA were acting responsibly when they recommended the pause.
"I really think, and I really hope that the American public will look at this pause and look at what we have done during this pause as an indication of how safe the vaccine system and the vaccine pipeline is in this country," said Romero.
Will this impact vaccine supply in the US?
President Joe Biden and other officials have said whatever decision is made about the Covid-19 vaccine, it will not hinder the vaccination effort in the US.
The FDA requested Monday that manufacturing of the J&J vaccine be paused at a Baltimore Emergent BioSolutions facility while it conducts an investigation into contamination that affected at least one batch of J&J's vaccine.
"We want to convey to the American public we have two vaccines that are readily available -- the Pfizer and Moderna -- and people should continue to roll up their sleeves to get vaccinated," CDC Director Dr. Rochelle Walensky said last week.
Walensky said that while the CDC conducts a risk-benefit analysis of the J&J vaccine, the agency has reached out to more than 10,000 providers to inform them about what to watch out for, in case other people experience similar adverse events.
Those who have received the J&J vaccine within the last three weeks have a very low risk of developing the rare blood clot that will decrease over time, the CDC says. The agency recommends those who experience certain symptoms, including sudden, severe headache, leg swelling and shortness of breath, seek immediate medical treatment.