Europe’s drug regulator said on Friday it is reviewing rare blood clots in four people in the United States who received Johnson & Johnson’s COVID-19 vaccine.
Johnson & Johnson (J&J) said it was aware of the rare reports of blood clots in individuals given its COVID-19 vaccine, and was working with regulators to assess the data and provide relevant information.
“At present, no clear causal relationship has been established between these rare events and the Janssen COVID-19 vaccine,” the company said in a statement.
Of the four serious cases of clotting and low platelets, three occurred in the United States during the rollout of J&J’s vaccine from its Janssen unit, the European Medicines Agency (EMA) said. That was in addition to one person who died from a clotting disorder reported in J&J’s clinical trial.
The U.S. Food and Drug Administration said it is aware of a few reports of individuals who had serious blood clots – sometimes linked with low levels of blood platelets – after they received the J&J vaccine, and noted that these conditions can have many different causes.
“We have not found a causal relationship with vaccination and we are continuing our investigation and assessment of these cases. Our analysis of the data will inform the potential need for regulatory action,” the agency said.
Nearly 5 million people in the United States had received J&J’s vaccine, according to the U.S. Centers for Disease Control and Prevention.
The report from the EMA is the first to mention a probe of blood clots associated with the J&J vaccine. The FDA said it was aware of the EMA’s statement and provided the agency with the data that formed the basis of its report.
The European Medicines Agency’s safety committee has also been looking at how AstraZeneca’s COVID-19 vaccine is associated with very rare cases of unusual blood clots and said it was now reviewing reports of capillary leak syndrome in people given AstraZeneca’s vaccine.
In its report on Friday, EMA’s safety committee said unusual blood clots linked with low blood platelets should be listed as very rare side effects of the AstraZeneca vaccine.
It has also started to investigate reports of capillary leak syndrome – which causes blood vessel swelling and a drop in blood pressure – in five people who received the AstraZeneca vaccine. The safety panel said it was not clear whether these were linked with the vaccine.
Some countries in Europe and Asia have restricted the use of AstraZeneca’s vaccine, however, regulators have said the vaccine outweigh the risks.
J&J’s single-dose vaccine has been approved for EU use, but a rollout is yet to begin. It is mainly being used in the United States currently.
The J&J and AstraZeneca shots are two of the four approved COVID-19 vaccinations in Europe.