OTTAWA — Drug safety regulators in Europe and the United Kingdom said Thursday they have enough evidence to conclude the benefits of the Oxford-AstraZeneca vaccine still outweigh the risks, but both are doing more study because they cannot yet say if the vaccine had any link to a small number of very rare blood clots in the brain.
Emer Cooke, executive director of the European Medicines Agency, said the its risk committee had reached “a clear, scientific conclusion” that “this is a safe and effective vaccine.”
“Its benefits in protecting people from COVID-19, with the associated risks of death and hospitalization outweigh the possible risks,” Cooke said.
“The committee also concluded that the vaccine is not associated with an increase in the overall risk of thromboembolic events or blood clots.”
But the EMA is changing the warning label on the vaccine because it does not have conclusive evidence about whether the vaccine may be linked to 18 cases of rare blood clots in the brain, and seven cases where patients developed extremely low levels of platelets and tiny blood clots in multiple blood vessels.
The cases include patients in Germany, Italy, Norway, Spain, the U.K. and India, out of nearly 20 million people vaccinated with AstraZeneca in the U.K., Europe and India.
“The evidence we have is, at the moment, not sufficient to conclude with certainty whether these adverse events are indeed caused by the vaccine or not,” said Dr. Sabine Straus, chair of the EMA’s Pharmacovigilance and Risk Assessment Committee.
The U.K. Medicines and Healthcare Products Regulatory Agency issued similar news earlier Thursday, saying it firmly believes the vaccine is safe and effective but is doing a more detailed study looking at blood clots in the brain.
More than 15 European nations halted use of the AstraZeneca vaccine after there were reports of blood clots in about three dozen patients.
Health Canada did not halt its use here.
Deputy chief public health officer Dr. Howard Njoo said Canada was monitoring all the evidence closely.
“The fact is that all four COVID-19 vaccines authorized by Health Canada meet our country’s high standards for safety, and provide a high degree of protection against severe illness and death related to COVID-19,” said Njoo.
The U.K. review looked at reports of cases of blood clots, hospital admission records and doctor’s patient files and concluded the patients who developed blood clots in veins are not caused by the vaccine.
They are looking more closely now at five reports in the U.K. of patients developed a rare blood clot in the brain, and lowered platelet counts following vaccination, but said the issue can occur naturally and there is no proven link to the vaccine.
Cooke said the warning label is not meant to advise people against getting the vaccine but to raise awareness so people who do get it are told what signs to look out for when it comes to blood clots.
“If it was me, I would be vaccinated tomorrow,” she said.
Cooke said there are thousands of people dying every day from COVID-19 and this vaccine is effective against the novel coronavirus.
Canadian provinces began administering 500,000 doses of the AstraZeneca vaccine last week. Canada’s doses are not made in the same place as the European or U.K. doses.
Dr. Supriya Sharma, the chief medical adviser at Health Canada, said last week there was no biological explanation to show a link between the vaccine and blood clots.
Thrombosis Canada issued a statement March 11 saying in general vaccines are not linked to the development of blood clots and it had no evidence that the AstraZeneca vaccine was any different.
AstraZeneca said it reviewed the safety records of 17 million patients who received the vaccine in Europe and the U.K. and found no causal link between it and blood clots.