The European Union’s drug regulatory agency is studying cases of blood clots among four people who received the Johnson & Johnson coronavirus vaccine, although the link between the two is still unclear.
The European Medicines Agency (EMA) said on Friday that serious cases of “unusual blood clots with low blood platelets” have been reported in four people who received Johnson & Johnson inoculation. according to Reuters.
Three of the cases occurred in the United States during the deployment of the vaccine, while one person who participated in the Johnson & Johnson clinical trial died of a clotting disorder.
According to the Centers for Disease Control and Prevention (CDC), approximately 5 million people in the U.S. have already received the Johnson & Johnson vaccine.
The company said in a statement Friday that it was aware of the blood clot reports and was working with regulators to review safety data.
“At present, no clear causal relationship has been established between these rare events and the Janssen COVID-19 vaccine,” Johnson & Johnson told Reuters.
The Hill has contacted the vaccine developer for additional information.
Reports arrive as there has already been widespread concern about reported blood clots in people who received the AstraZeneca vaccine, which has not been federally authorized for emergency use in the U.S.
An EMA security committee said Wednesday there was a “possible link” between AstraZeneca inoculation and rare blood clots, but added that the benefits of receiving the vaccine outweigh the potential risks.
The committee said so unusual blood clots with low blood platelets should be listed as very rare side effects of the vaccine, although it did not establish new restrictions on inoculation.
However, some European countries have imposed limits on the distribution of the AstraZeneca vaccine, including those advising young age groups not to receive it.
Most cases of blood clots have been reported in women under 60 in the two weeks following the AstraZeneca vaccine.
The Johnson & Johnson and AstraZeneca vaccines are two of four that have been approved in Europe, although the deployment of the Johnson & Johnson single dose has not yet begun across the region.