EU Hits AstraZeneca Vaccine with Another Blood Condition for Side Effect List

EMA_Niels Wenstedt/BSR Agency/Getty

Niels Wenstedt/BSR Agency/Getty Images

The AstraZeneca COVID-19 vaccine takes another hit to its safety profile as the European Medicines Agency adds a new side effect to the label of its shot. 

The EMA identified a rare blood condition, capillary leak syndrome, as a potential side effect of AstraZeneca’s Vaxzevria. The condition causes plasma leaks from blood vessels into neighboring body cavities and muscles. Blood pressure experiences a sharp drop as a result, and, left untreated, the disorder can lead to organ failure and death. 

The first to approve the emergency use of Vaxzevria, the UK has administered 40 million doses of the vaccine so far. Of those, there have been eight reports of capillary leak syndrome, with two of the eight in people with a history of the condition.  

"The incidence of these reports is lower than the number of cases expected to occur by chance in the absence of vaccination of this extremely rare condition and the current evidence does not suggest that capillary leak syndrome is caused by the COVID-19 Vaccine AstraZeneca," said Britain’s MHRA Chief Executive June Raine.  

While the MHRA has not yet issued official precautionary advice, the EMA has determined that people who have previously been diagnosed with capillary leak syndrome (CLS) should not receive the AstraZeneca vaccine. At this point, MHRA does not see a causal link with the vaccine.  

AstraZeneca pointed to the extreme rarity of CLS cases – less than 1 in 10 million vaccinated – and said, "We are working actively, in collaboration with regulatory authorities, on risk minimization measures... that includes information to those being vaccinated...information to drive early diagnosis and intervention, and appropriate treatment.” 

This hasn’t been the only negative side effect discovered for Vaxzevria. A research report associated the shot with a bleeding disorder called immune thrombocytopenic purpura (ITP). Out of the 2.53 million evaluated in Scotland, the adults inoculated with the first dose of the AZ vaccine had a slightly higher risk for ITP than those who’d received their first shot from Pfizer. The disorder causes bruising in some and severe bleeding in others. The risk was about 1.13 cases per 100,000, with no fatalities. ITP is treatable. 

Both the AstraZeneca and Johnson & Johnson vaccines have also been associated with rare blood clotting disorders.  

Although the vaccine has been approved for emergency use by the UK’s MHRA, the EU’s European Medicines Agency, Vietnam, Australia, Canada, Mexico, and many countries in Asia and South America, the FDA has yet to budge on approval for the US. The FDA is waiting on results from a large-scale trial after taking issue with the company’s initial trial data.  

Additionally, the EMA is continuing to look into cases of heart inflammation – myocarditis and pericarditis – following primarily those who received the Pfizer/BioNTech and Moderna mRNA vaccines, but also after the J&J and AZ viral vector vaccines.  

Though a causal relationship has not been established, higher-than-expected heart inflammation has been found in young men in the US who received both doses of the mRNA shots in particular.  

According to a data project at the University of Oxford, 12.7% of the world’s population have received at least one dose of a COVID-19 vaccine. Over 33 million doses are administered each day.  

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