Regulators are examining potential links between the Oxford/AstraZeneca vaccine and rare blood clots
(Picture: REUTERS)There is a link between AstraZeneca's Covid vaccine and very rare blood clots in the brain but the possible causes remain unknown, a senior official at the European Medicines Agency (EMA) has said.
Marco Cavaleri, chairman of the vaccine evaluation team at the EMA, told Italian newspaper Il Messaggero there is a “link” between the jab and the reported illnesses.
He said: “In my opinion we can now say it, it is clear that there is an association with the vaccine. However, we still do not know what causes this reaction.”
Cavaleri added that the regulator would not likely be in a position to give an indication regarding the age of individuals to whom the AstraZeneca jab should be given.
He did not provide evidence to support his comments.
AstraZeneca was not immediately available for comment when contacted by the Reuters news agency. It has said previously its studies have found no higher risk of clots because of the vaccine.
The regulator has consistently said the benefits outweigh the risks as it investigates 44 reports of an extremely rare brain clotting ailment known as cerebral venous sinus thrombosis (CVST) out of 9.2 million people in the European Economic Area who have received the AstraZeneca vaccine.
The World Health Organization has also backed the vaccine and it still approved for use by the UK.
The UK’s medicines regulatory body has said it has yet to make a decision on any regulatory action relating to the vaccine, following reports it is considering restricting use of the vaccine in younger people.
It was claimed on Monday that the Medicines and Healthcare Products Regulatory Agency (MHRA) was considering the restrictions for its use with under-30s.
The EMA said last week that its review had at present not identified any specific risk factors, such as age, gender or a previous medical history of clotting disorders, for these very rare events. A causal link with the vaccine is not proven, but is possible and further analysis is continuing, the agency said.
A high proportion among the reported cases affected young and middle-aged women but that did not lead EMA to conclude this cohort was particularly at risk from AstraZeneca's shot.
The EMA is expected to give an update of its investigation on Wednesday.
Some countries, including France, Germany and the Netherlands, have suspending the use of the vaccine in younger people while the investigations continue.
Scientists are exploring several possibilities that might explain the extremely rare brain blood clots that occurred in individuals in the days and weeks after receiving the AstraZeneca vaccine.
European investigators have put forward one theory that the vaccine triggers an unusual antibody in some rare cases; others are trying to understand whether the cases are linked with birth control pills.
But many scientists say there is no definitive evidence and it is not clear whether or why AstraZeneca's vaccine would cause an issue not shared by other vaccines that target a similar part of the coronavirus.
In a separate interview, Armando Genazzani, a member of the EMA's Committee for Medicinal Products for Human Use (CHMP), told La Stampa daily that it was “plausible” that the blood clots were correlated to the AstraZeneca vaccine.
