Canada is pausing the use of the AstraZeneca COVID-19 vaccine to adults under the age of 55.
This after Europe reported several rare but serious cases of blood clots known as vaccine-induced pro-thrombotic immune thrombocytopenia (VIPIT) following the use of the vaccine.
Dr. Howard Njoo, Canada’s deputy chief public health officer, described it as a “precautionary measure” pending a further risk/benefit analysis from Health Canada.
“From what is known at this time, there is substantial uncertainty about the benefit of providing AstraZeneca vaccine to adults under 55 years of age given the potential risks associated with VIPIT,” says Dr. Njoo.
Dr. Njoo says similar adverse events have not been reported in Canada.
Dr. Shelley Deeks, the vice-chair of the National Advisory Committee on Immunization, says it has been fatal overseas.
“Based on available information, the case fatality of this condition is approximately 40 per cent,” says Dr. Deeks.
Dr. Njoo says the reported adverse events have occurred primarily in women. He says that could be because more women received the vaccine than men.
While the use of the vaccine has been paused in adults under the age of 55, Dr. Njoo says those over 55 may still be offered it.
“Given the increased risk of hospitalization and death due to COVID-19 in this population and since VIPIT reports have been even rarer in that age group,” he says.
Dr. Njoo says people who have already been vaccinated with AstraZeneca for more than 20 days have no cause for concern.
Those vaccinated for less than 20 days should seek medical attention if they develop any of the following symptoms four days or more after receiving the vaccine: shortness of breath, chest pain, leg swelling, persistent abdominal pain, sudden onset of severe or persistent worsening headaches or blurred vision, and skin bruising other than at the vaccination site.
“Decisions on the type of second dose that will be offered to those who have been vaccinated with AstraZeneca will be determined based on the latest evidence and research,” says Dr. Njoo, noting those who received the vaccine do not need a second dose for up to 16 weeks after their first.
With files from Robert Lothian.
