The FDA added a warning that Johnson & Johnson's COVID-19 vaccine may trigger Guillain-Barré syndrome (GBS) in a small number of people in a on Monday.
Of the 12.5 million Americans who received this vaccine, about 100 people reported having GBS in the Vaccine Adverse Event Reporting System (). Of these reports, 95 of them were serious and required hospitalization, and there was one reported death, an FDA spokesperson told 乌鸦传媒.
The warning was added to the Johnson & Johnson's COVID-19 vaccine fact sheets for and . It states that adverse event reports suggest an increased risk of Guillain-Barré syndrome in the 42 days after vaccination. Patients should seek medical attention right away if they develop weakness or tingling sensations especially in legs or arms that worsens and spreads, difficulty walking, difficulty with facial movements, double vision or inability to move eyes, or difficulty with bladder control or bowel function.
GBS is an acquired demyelinating polyneuropathy that often begins in the lower extremities and ascends over time with loss of reflexes, causing muscle weakness, or in the most severe cases, paralysis. Some cases start a few days or weeks after respiratory or gastrointestinal viral infection. Often, GBS is reversible.
No similar signal has been identified with the Moderna and Pfizer-BioNTech COVID-19 vaccines, the FDA spokesperson said.
"Although the available evidence suggests an association between the Janssen vaccine and increased risk of GBS, it is insufficient to establish a causal relationship," the FDA said in a statement. "Importantly, the FDA has evaluated the available information for the Janssen COVID-19 vaccine and continues to find the known and potential benefits clearly outweigh the known and potential risks."
The warning comes days after the Pharmacovigilance Risk Assessment Committee (PRAC) of the to the product information for AstraZeneca's COVID-19 vaccine, alerting prescribers and patients to potential risk of GBS.
"The Committee has assessed all the available evidence, including cases reported to the European database for suspected side effects (EudraVigilance) and data from the scientific literature, but at this stage the available data neither confirms nor rules out a possible association with the vaccine," PRAC reported.
Both the Johnson & Johnson and AstraZeneca shots are adenovirus vector vaccines. Two recently published reports detailed cases of an unusual variant of GBS involving severe bilateral facial paresis associated with the AstraZeneca shot involving patients in England and India. A case report of a woman who developed GBS 10 days after receiving the Johnson & Johnson vaccine in a clinical trial in Boston also was published this year.
"We have been in discussions with the U.S. Food and Drug Administration and other regulators about rare cases of the neurological disorder, Guillain-Barré syndrome, that have been reported following vaccination with the Janssen COVID-19 vaccine," . "The chance of having this occur is very low, and the rate of reported cases exceeds the background rate by a small degree."