Federal health agencies in the United States paused their use of the Johnson & Johnson coronavirus vaccine on Tuesday, urging states across the country to do the same.
The move comes after six people who received the J&J vaccine in the country developed a rare disorder involving blood clots called cerebral venous thrombosis. Nearly seven million doses of the jab have been administered across the US.
The Food and Drug Administration (FDA) and the Centres for Disease Control and Prevention (CDC) said in an announcement on Tuesday that the decision comes “out of an abundance of caution”.
The health agency has said that the “adverse events appear to be extremely rare” and that the pause will allow healthcare providers to “plan for proper recognition and management” of the blood clots.
What do we know about the six cases?
In a joint release, the FDA and the CDC confirmed that the six recipients who had an adverse reaction to the jab were all women between the ages of 18 and 48.
Their symptoms occurred six to 13 days after vaccination, according to a press release.
The New York Times reported on Tuesday that one woman has died while another in Nebraska remains in critical condition.
In the state, Douglas County health officials said on Friday an individual in their late 40s had experienced "a significant medical event involving thromboembolic occurrence (blood clots)" two weeks after receiving the J&J vaccine, according to KETV.
What does this mean?
Health officials in Europe have so far said that as of this time it is not clear whether there is a causal association between the J&J shot and the blood clots.
According to data from the CDC, just under seven million people have received a shot of the J&J vaccine so far, with the FDA reporting six recorded cases of blood clots from this number.
Over 16 million doses of the shot have been delivered to states across the country. While the FDA’s announcement only affects federal vaccination sites it is expected that the other state vaccination programmes will follow their lead.
Use of other coronavirus vaccinations such as the Pfizer-BioNtech and Moderna jabs is not expected to be affected.
New York has become the first state to follow the federal agencies’ lead and pause the use of the J&J shot while a handful of blood clot incidents are investigated, the state health commissioner said.
Johnson & Johnson has also “made the decision to proactively delay the rollout of our vaccine in Europe” while the clots are investigated. Hundreds of thousands of doses of the vaccine were due to be shipped to Europe in the coming weeks.
What happens next?
The FDA confirmed that the CDC will convene a meeting of the Advisory Committee on Immunization Practices (ACIP) on Wednesday to further review these cases and assess their potential significance.
“This is important to ensure that the health care provider community is aware of the potential for these adverse events and can plan due to the unique treatment required with this type of blood clot,” they said, adding: “Until that process is complete, we are recommending this pause.”
The European Medicines Agency (EMA) has already started reviewing the J&J vaccine to assess reports of blood clots in people who received the shot, it said.
“These reports [from the US] point to a ‘safety signal’, but it is currently not clear whether there is a causal association between vaccination” with the Johnson & Johnson shot, the EMA said.
Should I be worried?
The FDA stressed that “right now, these adverse events appear to be extremely rare”.
According to estimates from the CDC, up to 900,000 men, women and children are affected by blood clots each year, leading to around 100,000 deaths.
The FDA said that treatment of this specific type of blood clot is different from the treatment that might typically be administered and that therefore more examination of the cases is needed.
“Covid-19 vaccine safety is a top priority for the federal government, and we take all reports of health problems following Covid-19 vaccination very seriously,” the FDA said.
Over 120 million people, which equates to 36.4 per cent of the US population, have received at least one dose of a coronavirus shot since the vaccine began in December.
The FDA said that people who have received the J&J vaccine who develop a severe headache, abdominal pain, leg pain, or shortness of breath within three weeks of their vaccination should contact their health provider.