EMA’s safety committee (PRAC) has concluded that people who have previously had capillary leak syndrome must not be vaccinated with Vaxzevria (formerly COVID-19 Vaccine AstraZeneca). The Committee also concluded that capillary leak syndrome should be added to the product information as a new side effect of the vaccine, together with a warning to raise awareness among healthcare professionals and patients of this risk.

The Committee carried out an in-depth review of 6 cases of capillary leak syndrome in people who had received Vaxzevria. Most of the cases occurred in women and within 4 days of vaccination. Three of those affected had a history of capillary leak syndrome and one of them subsequently died. As of 27 May 2021, more than 78 million doses of Vaxzevria had been administered in the EU/EEA and the UK.

Capillary leak syndrome is a very rare, serious condition that causes fluid leakage from small blood vessels (capillaries), resulting in swelling mainly in the arms and legs, low blood pressure, thickening of the blood and low blood levels of albumin (an important blood protein).

People who have been vaccinated with Vaxzevria should seek immediate medical assistance if they experience rapid swelling of the arms and legs or sudden weight gain in the days following vaccination. These symptoms are often associated with feeling faint (due to low blood pressure).  

The PRAC will continue to monitor for cases of the condition and will take any further actions necessary. The PRAC has also asked AstraZeneca, the company marketing Vaxzevria, for further information about a possible mechanism for the development of capillary leak syndrome following vaccination.