BRUSSELS — The European Medicines Agency (EMA) announced Wednesday that its safety committee is reviewing very rare cases of unusual blood clots that occurred in the United States following the use of Janssen's COVID-19 vaccine.

The EMA has initiated review of Johnson & Johnson’s (J&J) single-shot COVID-19 vaccine over reports of rare blood clots in four individuals in the US.

US health and disease control bodies recommended Monday that the use of the vaccine should be paused while they review six reported cases in the United States. More than 6.8 million doses of the vaccine have been administered, said the EMA based in Amsterdam in a press release.

Janssen has announced their decision to delay the rollout of the vaccine in the EU while investigations continue. The vaccine was authorized in the EU on March 11, 2021, but widespread use of the vaccine within the EU has not yet started.

EMA said it is investigating all the cases reported and will decide whether regulatory action is necessary. While its review is ongoing, EMA said it remains of the view that the benefits of the vaccine in preventing COVID-19 outweigh the risks of side effects.

COVID-19 Vaccine Janssen is a vaccine for preventing coronavirus disease 2019 (COVID-19) in people aged 18 years and older. The most common side effects with COVID-19 Vaccine Janssen are usually mild or moderate and get better within one or two days after vaccination, it noted.

The company noted that it is aware of the blood clot issue linked to the vaccine and is working with the agency to analyze the data and make available necessary information, Reuters reported.

In an emailed statement to the news agency, J&J said: “At present, no clear causal relationship has been established between these rare events and the Janssen COVID-19 vaccine.”

According to EMA, of the four serious cases of clotting and low platelets, three were reported in the US during the vaccine rollout from J&J’s Janssen unit while one person had died from a clotting disorder during the clinical trial.

The US Food and Drug Administration (FDA) noted that it is aware of the serious blood clot reports and said that these conditions could have various causes.

Meanwhile, the EMA’s safety committee is also analyzing how AstraZeneca’s COVID-19 vaccine is linked to very rare cases of unusual blood clots and noted that reports of capillary leak syndrome in individuals receiving AstraZeneca vaccine are being reviewed.

Capillary leak syndrome leads to blood vessel swelling and causes a drop in blood pressure.

Last week, the Philippines Department of Health (DOH) adopted the FDA’s recommendation to temporarily put the use of the AstraZeneca vaccine on hold for individuals aged below 60 years. — Agencies