FDA Limits Use Of Johnson & Johnson Vaccine Due To Blood Clot Risk
Johnson & Johnson’s coronavirus vaccine is now only authorized for U.S. adults who are unable to receive other vaccines, the Food and Drug Administration announced Thursday, citing the Johnson & Johnson vaccine’s risk of potentially life-threatening blood clotting side effects.
Due to the vaccine’s risk of causing thrombosis with thrombocytopenia syndrome (TTS), a blood-clotting disorder that can cause stroke or heart attack, it should not be used unless other vaccines are unavailable or determined to be clinically inappropriate, the FDA said.
TTS is rare, affecting about 1 person in 250,000 who takes Johnson & Johnson’s vaccine, but it is far more serious than the usually mild heart inflammations sometimes associated with Pfizer and Moderna’s Covid-19 vaccines.
Johnson & Johnson’s vaccine has also been linked to rare instances of Guillain-Barré syndrome—an immune disorder that can cause paralysis—though the FDA did not cite this in its decision to narrow the vaccine’s authorization.
Johnson & Johnson’s vaccine still has a role in pandemic response, and the decision to narrow its authorization demonstrates the thoroughness of the FDA’s safety systems, said Dr. Peter Marks, director of the FDA’s Center for Biologics Evaluation and Research, in a statement.
In response to the decision, Johnson & Johnson said it had updated its vaccine fact sheet to increase awareness of blood clotting side effects, but pointed out that the available data continues to show getting Johnson & Johnson’s vaccine is safer than getting no vaccine.
Pfizer and Moderna’s Covid-19 vaccines work by delivering a piece of messenger RNA (mRNA) that instructs cells to build a harmless piece of coronavirus protein, creating an immune response against the coronavirus. In contrast, the Johnson & Johnson vaccine delivers instructions to build the immunity-creating coronavirus protein using a cold virus that has been rendered harmless and is incapable of reproducing. Since it was authorized for emergency use in February 2021, Johnson & Johnson’s vaccine has been found less effective than Pfizer and Moderna’s vaccines. Most clinical trials have found Johnson & Johnson’s vaccine to be around 68% effective at preventing hospitalization from Covid-19, far less than competing vaccines. In March, the Centers for Disease Control and Prevention recommended that people who have undergone a course of Johnson & Johnson’s vaccine get a booster from Pfizer or Moderna, which can create a stronger immune response and lessen the risk of TTS.
The CDC continues to recommend Johnson & Johnson’s vaccine for anyone who had a severe reaction after an mRNA vaccine shot or who would otherwise remain unvaccinated due to limited access to other vaccines.