EMA finds 'possible link' between Johnson & Johnson vaccine and rare blood clots

20 April 2021, 15:41 | Updated: 28 April 2021, 19:21

By Nick Hardinges

@NHardinges

Europe's medicines regulator has found a "possible link" between Johnson & Johnson's coronavirus vaccine and very rare blood clots.

The safety committee of the European Medicines Agency (EMA) concluded that unusual blood clots with low blood platelets should be listed as a "very rare" side effect of the vaccine.

However, the EMA concluded the overall benefits of the Janssen vaccine "outweigh the risks of side effects".

Officials reviewed eight cases reported in the United States, where more than seven million people have received the jab.

They said these cases were "were very similar to the cases that occurred with the Covid-19 vaccine developed by AstraZeneca".

Johnson & Johnson's Janssen jab is yet to be approved for use in the UK.

Read more: US recommends pause to Janssen jab rollout over blood clot reports

Read more: Johnson & Johnson one-dose Covid vaccine approved for EU use

Pfizer, Moderna and AstraZeneca: The Coronavirus Vaccines Explained

All cases of blood clots linked to the drug occurred in people under the age of 60, mostly women, and within three weeks of being inoculated.

The regulator said that based on the current available evidence, specific risk factors have not been confirmed.

In a statement, it explained: "Healthcare professionals and people who will receive the vaccine should be aware of the possibility of very rare cases of blood clots combined with low levels of blood platelets occurring within three weeks of vaccination.

"Covid-19 is associated with a risk of hospitalisation and death. The reported combination of blood clots and low blood platelets is very rare, and the overall benefits of Covid-19 Vaccine Janssen in preventing Covid-19 outweigh the risks of side effects."

Read more: Janssen Covid vaccine: Major trial launches in UK

Read more: Single-dose Janssen Covid-19 vaccine 66 per cent effective

The EMA said one "plausible explanation for the combination of blood clots and low blood platelets is an immune response, leading to a condition similar to one seen sometimes in patients treated with heparin called heparin induced thrombocytopenia, HIT".

Its committee noted that the blood clots occurred mostly at "unusual sites" such as in veins in the brain, in the abdomen and in arteries, together with low levels of blood platelets and sometimes bleeding.

It said that people taking the jab and health workers should be made aware of the potential very rare side effect, adding that prompt specialist medical treatment can help aid recovery and avoid complications.

Johnson & Johnson previously confirmed it will delay rollout of its single-dose vaccine across Europe after the US paused the administration of the jab to investigate reports of potentially dangerous blood clots.

The UK has 30 million doses of the vaccine on order, but it has not yet been signed off for use by the Medicines and Healthcare products Regulatory Agency (MHRA).

The doses are expected to arrive in the second half of 2021 if approved by the regulator. However, the Department of Health and Social Care said the decision to delay the rollout of the Janssen vaccine in Europe would not derail the UK's programme to offer a jab to all adults by the end of July.