United States regulators have added a new warning to Johnson & Johnson’s COVID-19 vaccine about links to a rare and potentially dangerous neurological reaction.
The Food and Drug Administration (FDA) announced the new warning on Monday, flagging reports of Guillain-Barre syndrome, an immune system disorder that can cause muscle weakness and occasionally paralysis. Health officials described the side effect as a “small possible risk” for those getting the shot.
The new warning will be included in pamphlets given to people getting the Johnson & Johnson shot. They should seek medical attention if they experience any symptoms, which include tingling sensations, trouble walking and double vision, the regulators said.
The action comes after the FDA and the Centers for Disease Control and Prevention (CDC) reviewed reports of about 100 people developing the syndrome after receiving the one-dose vaccine. Almost all of them were hospitalised and one person died, the FDA said.
Guillain-Barre syndrome occurs when the body’s immune system mistakenly attacks some of its nerve cells, causing muscle weakness and sometimes paralysis that typically is temporary. An estimated 3,000 to 6,000 people in the United States develop the syndrome each year, according to the CDC.
The number of cases reported in connection with Johnson & Johnson’s vaccine represents a tiny fraction of the nearly 13 million people in the US who have received the jab. Most cases were reported in men – mostly those who were 50 years old and above – and usually about two weeks after vaccination.
Johnson & Johnson said in a statement it has been discussing the reports with the FDA and other health regulators around the world.
The CDC said it would ask its panel of outside vaccine experts to review the issue at an upcoming meeting.
The government said the vaccines most used in the US, made by Pfizer and Moderna, show no risk of the disorder after more than 320 million doses have been administered.
Vaccines historically provide broad protection with little risk but come with occasional side effects just like other drugs and medical therapies. The three COVID-19 vaccines used in the US were each tested in tens of thousands of people, but even such huge studies cannot rule out extremely rare side effects.
The CDC and the FDA have been monitoring side effect reports submitted by physicians, drugmakers and patients to a federal vaccine safety database.
Guillain-Barre can be triggered by a number of infections, including flu, cytomegalovirus and Zika virus. But there have been rare cases in which people develop the disorder days or weeks after receiving certain vaccines.
Johnson & Johnson’s vaccine was highly anticipated because of its “one-and-done” formulation and easy-to-ship refrigeration. But early on, it was linked to another rare risk – blood clots – and the company has not been able to produce as much as expected because of problems at a Baltimore factory that helps make the shots.
The news comes as demand for COVID vaccines in the US continues to decrease, with only about 430,000 shots being administered a day. The peak seven-day average was around 3.5 million, back in April.
Cases are rising rapidly in under-vaccinated states in the country’s Midwest and south, with the highly contagious Delta variant now dominant.