EU watchdog evaluates possible link between Johnson & Johnson jab and blood clots

By Jane Byrne

- Last updated on GMT

© GettyImages/Fokusiert
© GettyImages/Fokusiert

Related tags COVID-19 Astrazeneca Johnson & johnson blood clots

The European Medicines Agency (EMA) is evaluating a possible link between blood clots and Johnson & Johnson’s COVID-19 vaccine, while also reviewing reports of a bleeding condition in some individuals who received AstraZeneca’s COVID-19 shot.

It announced today that its safety committee, PRAC, is investigating thromboembolic events after vaccination with COVID-19 Vaccine Janssen.

PRAC has started a review of a safety signal to assess reports of thromboembolic events (formation of blood clots, resulting in the obstruction of a vessel) in people who received COVID-19 Vaccine Janssen.

“Four serious cases of unusual blood clots with low blood platelets have been reported post-vaccination with COVID-19 Vaccine Janssen. One case occurred in a clinical trial and three cases occurred during the vaccine rollout in the USA. One of them was fatal,”​ said the EU watchdog.

COVID-19 Vaccine Janssen is currently only used in the US, under an emergency use authorization (EUA).

The shot was authorized in the EU on March 11, 2021, but the vaccine rollout has not started yet in any EU country. Although, campaigns using the vaccine are expected to get going in Europe in the next few weeks, said the EU regulatory body.

These reports point to a ‘safety signal’, but it is currently not clear whether there is a causal association between vaccination with COVID-19 Vaccine Janssen and these conditions.

“PRAC is investigating these cases and will decide whether regulatory action may be necessary, which usually consists of an update to the product information,”​ said the EMA.

The regulator said it will communicate further once its evaluation has concluded.

Company reaction 

In a statement emailed to BioPharma-Reporter, Johnson & Johnson said the safety and well-being of the people who use its products is its number one priority.

"We share all adverse event reports about individuals receiving our COVID-19 vaccine, along with our assessment of these reports, with health authorities in compliance with regulatory standards. We are aware that thromboembolic events including those with thrombocytopenia have been reported with all COVID-19 vaccines.

"Our close tracking of side effects has revealed a small number of very rare events following vaccination. At present, no clear causal relationship has been established between these rare events and the COVID-19 vaccine Janssen. 

"We continue to work closely with experts and regulators to assess the data and support the open communication of this information to healthcare professionals and the public to help ensure that, in the event of a very rare illness, appropriate steps can be taken for quick diagnosis and treatment."

COVID-19 Vaccine Janssen

Johnson & Johnson's vaccine is manufactured using adenovirus type 26 (Ad26): which delivers a piece of the DNA used to make the “spike” protein of the SARS-CoV-2 virus.

It is based on Janssen’s Ad26 vector platform, which is already used with other vaccines (the Ad26.ZEBOV/MVA-BN-Filo Ebola vaccine was approved by the European Medicines Agency in July; while investigational vaccines are being developed against Zika, filovirus, HIV, HPV, malaria, and respiratory syncytial virus).

The vaccine was found to be 67% effective at reducing moderate to severe COVID-19 cases in a global Phase 3 trial. This included a cohort in South Africa, allowing the company to also determine the vaccine is 52% effective against the B.1.351 strain.

As a one-shot vaccine, it has the potential to offer a logistical advantage and help vaccinate more people more quickly.

Bleeding syndrome probe

Earlier this week, PRAC concluded​ that unusual blood clots with low blood platelets should be listed as very rare side effects of Vaxzevria, previously COVID-19 Vaccine AstraZeneca. 

In further developments today, the EMA said it is also reviewing reports of a bleeding condition in some individuals who had received AstraZeneca's jab.

PRAC has started a review of a safety signal to assess reports of capillary leak syndrome in people who were vaccinated with Vaxzevria.

“Five cases of this very rare disorder, characterized by leakage of fluid from blood vessels causing tissue swelling and a drop in blood pressure, were reported in the EudraVigilance database​,” said the regulator.

At this stage, it is not yet clear whether there is a causal association between vaccination and the reports of capillary leak syndrome, it stressed.

PRAC said it will evaluate all the available data to decide if a causal relationship is confirmed or not.

“In cases where a causal relationship is confirmed or considered likely, regulatory action is necessary in order to minimize the risk. This usually takes the form of an update of the summary of product characteristics and the package leaflet.”

Related topics Markets & Regulations COVID-19

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