Federal officials expect their recommended pause on Johnson & Johnson COVID-19 vaccines will last "a matter of days," the head of the U.S. Food and Drug Administration said Tuesday.
Acting FDA Commissioner Dr. Janet Woodcock said the exact time frame will depend on what officials learn over the next few days in their review of six cases of a severe blood clot reported after receiving the J&J shot, which she said seems to be "extremely rare."
The FDA and the Centers for Disease Control and Prevention on Tuesday announced they were recommending a pause on delivering J&J vaccines while those reports of a combination of the blood clot and a low platelet count — from six women in the U.S. between the ages of 18 and 48, among a pool of more than 6.8 million J&J doses administered nationwide — are investigated. Subsequently, the Massachusetts Department of Health directed providers here to stop giving J&J vaccines while the review plays out.
Woodcock said the message to those who have not yet been vaccinated would be "to get vaccines that are available to them, because the risks from the pandemic are significant, and the government is really looking into, very carefully, any safety problems so that they can be managed properly with this particular vaccine and all vaccines."
On a call with Woodcock and other officials, Dr. Anne Schuchat, the CDC's principal deputy director, said the pause would give time to prepare the health care system to recognize and treat any potential patients with blood clots or low platelet counts post-vaccination.
For the particular clot involved, known as cerebral venous sinus thrombosis or CVST, treatment with the anticoagulant drug heparin can be dangerous, and health officials are advising that providers use alternative treatments.
"I know this has been a long and difficult pandemic and a very long year and a half, and that people are tired of the steps that they need to take and are keen to be able to be vaccinated. The steps we're taking today are meant to make sure that the healthcare system is ready to diagnose, treat and report, and that the American public has the information we need to stay safe," Schuchat said.
For people who received a J&J vaccine more than a month ago, Schuchat said the risk "is very low at this time" and those who received it in the past couple weeks should contact their health provider and seek treatment if they experience severe headaches, abdominal pain, leg pain or shortness of breath. She said those symptoms differ from the mild flu-like symptoms some people experience shortly after getting the shot.
"Importantly, there are three vaccines available, and we are not seeing the clotting events with low platelet counts with the other two vaccines," Schuchat said.
She said people who have Pfizer or Moderna vaccine appointments can continue with their immunizations, and the federal government will work with its partners to reschedule those with upcoming J&J appointments.
Dr. Peter Marks, director of the FDA's Center for Biologics Evaluation and Research, said officials have not received similar reports arising from the 180 million doses administered so far of Pfizer or Moderna vaccines.
He said officials are speculating that one probable cause may be a specific immune response "that occurs very, very rarely after some people receive the vaccine, and that immune response leads to activation of these platelets and these extremely rare blood clots."
Marks said the recommended pause is not a mandate, and that if an individual patient and their health care provider together "determined that the benefit-risk for that individual patient is appropriate, we're not going to stop that provider from administering that vaccine."
White House COVID-19 Response Coordinator Jeff Zients said in a statement that the FDA and CDC's move would "not have a significant impact" on the Biden Administration's vaccine plan. He said the U.S. has secured enough Moderna and Pfizer doses for 300 million Americans and plans to make 28 million of those doses available this week.
Johnson & Johnson officials released a statement saying that the safety and well-being of people who use their products are the company's top priority. They said they had also been reviewing the six U.S. cases with European health authorities and "made the decision to proactively delay the rollout of our vaccine in Europe."
European regulators' review of an AstraZeneca COVID-19 vaccine, which is not in use in the U.S., found that the AstraZeneca vaccine may be associated with very rare cases of blood clots associated with low platelet levels, but it was not associated with an increase in the overall risk of blood clots and that its benefits in combating the threat of COPD-19 outweighed the risk of side effects.
Woodcock said the CDC is "in constant contact with the regulators worldwide and looking at adverse events experienced in different regions."
As for the duration of the pause, Woodcock said, "The time frame will depend obviously on what we learn in the next few days, however we expect it to be a matter of days for this pause."
Dr. David Rosman, president of the Massachusetts Medical Society, called the federal government's move "entirely appropriate" and said the CDC and FDA's "adherence to transparency, safety and the scientific process in response to a potential adverse reaction which fewer than one in a million patients have suffered should be reassuring to all those who have been vaccinated and those in line."
"COVID-19 remains present and dangerous and vaccination continues to be an integral component in our quest to come out of the pandemic," Rosman said. "The dramatic decline in hospitalizations and deaths among the at-risk populations that have been vaccinated illustrate the efficacy of the vaccines."