The European Medicines Agency (EMA) found a “possible link” between the development of very rare blood clots and the covid-19 vaccine developed by pharmaceutical company Janssen, but confirmed that the benefit-risk balance of this preparation remains “positive”.
After two weeks of research into six cases of very rare thromboembolism detected in patients vaccinated with Janssen in the United States, the EMA decided to add to the vaccine package leaflet a warning of the potential, very small risk of developing blood clotting, but continues to recommend its use in the European Union (EU).
“Very rare side effects”
At a meeting of the EMA’s Safety Committee (PRAC) on Tuesday (20.04.2021), European scientists concluded that “these events should also be included as very rare side effects” of the vaccine, as they have already recommended for the drug AstraZeneca.
“The committee took into account all currently available tests, including eight U.S. reports of severe cases of unusual blood clots associated with low blood platelet levels, one of which had a fatal outcome,” the EMA added in a statement, which compared these cases to the thrombus that occurred with the AstraZeneca vaccine.
All cases occurred in people under the age of 60, within three weeks of vaccination, and were mostly women, notes the European regulator, who warns that, from current evidence, “no specific risk factors have been confirmed”, such as age, sex and medical history, of development of these symptoms.
The Agency considers that healthcare professionals and patients receiving the Janssen vaccine “should be aware of the possibility of very rare cases of blood clotting combined with low blood platelets within three weeks of vaccination.”
“Benefits outweigh side effects”
But, beyond adding this information to the product, the EMA considers that the risk associated with covid-19, a disease that can involve hospitalization or death of patients, remains greater than the potential risk of developing blood clotting, so “the overall benefits of the vaccine outweigh the risks of side effects.”
In addition, it added that the use of available covid-19 vaccines will take into account “the pandemic situation and vaccine availability” in different EU countries, noting that “a plausible explanation” of these clotting cases is that they are an “immune response” similar to that seen in heparin treatments.
With these conclusions in hand, European countries will now decide what steps to take with regard to Janssen, which was the hope of many of them as the only single-dose vaccine available in the Community area and several States had last week received the first doses, which they keep stored until a decision has been taken after obtaining the opinion of the EMA.
As of April 13, more than 7 million people had received the Janssen vaccine in the United States, a country that has discontinued use until its investigation of these thromboembolic events was completed.
