其 他 安 全 警 示
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| Canada: Summary safety review: Janssen COVID-19 Vaccine: Assessing the potential risk of thrombosis in combination with thrombocytopenia (English only) |
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Health Canada announces that it reviewed the risk of unusual blood clots in combination with low blood platelets following vaccination with Janssen COVID-19 Vaccine to evaluate emerging information and determine if further measures are needed to mitigate the risk in Canada. This safety review was initiated after cases of blood clots with low platelets following administration of Janssen COVID-19 Vaccine were reported in the United States.
On 13 Apr 2021, the United States paused the use of the Janssen COVID-19 Vaccine as a precautionary measure, pending investigation of the reported cases of rare blood clots in combination with low levels of blood platelets following vaccination. At that time, Janssen COVID-19 Vaccine was only used in the United States, and over 6.8 million Americans had received the vaccine. Janssen COVID-19 Vaccine has been authorized in Canada since March 2021. The vaccine is expected to be distributed and administered in Canada in early May 2021.
Health Canada reviewed the available information from international databases, the manufacturer and international regulators. At the time of the review, Health Canada took into consideration all currently available information including 8 reports of blood clots associated with low platelets, 1 of which had a fatal outcome, from the United States. Of the 8 cases, 2 were found to be probably linked and 6 were possibly linked to the use of Janssen COVID-19 Vaccine. All cases occurred within 3 weeks following vaccination and mostly in women under 50 years of age. These cases are similar to those that were reported after administration of the AstraZeneca COVID-19 Vaccine and COVISHIELD2. A link between blood clots with low platelets and Janssen COVID-19 Vaccine is considered possible. The potential risk of blood clots and low platelets is very rare. Health Canada's findings are in line with the conclusions of international regulators. Based on the available information, no specific risk factors, such as age or gender, for these events have been identified.
A potential mechanism for the combination of blood clots with low platelets is the triggering of an immune response by the vaccine, leading to a condition similar to heparin-induced thrombocytopenia seen sometimes in patients treated with the blood thinner medication heparin.
Health Canada's review of the available information concluded that a link between the use of Janssen COVID-19 Vaccine and the risk of blood clots with low platelets is possible. The risk of these events is very rare. The overall benefits of Janssen COVID-19 Vaccine in preventing COVID-19 outweigh the risk of very rare events of blood clots in combination with low platelets. Health Canada's review of available information did not identify specific risk factors, such as age or gender, for these very rare events. Therefore, Health Canada is not restricting the use of the vaccine for certain populations or age groups. The risk of severe disease associated with COVID-19 illness varies with age and continues to change as the nature of the pandemic changes.
Health Canada has published information for vaccine recipients on signs and symptoms to monitor after vaccine administration and when to seek medical attention. Health Canada has also provided healthcare professionals with information to identify and promptly treat this condition according to current evidence and clinical guidelines. Health Canada worked with the manufacturer of Janssen COVID-19 Vaccine to update the Canadian Product Monograph (CPM) with this safety information. Health Canada also requested that the manufacturer update the risk management plan for the Janssen COVID-19 Vaccine to reflect the latest information about this safety issue, and to include plans for studies that will address remaining knowledge gaps. Health Canada will continue to monitor the safety of Janssen COVID-19 Vaccine. Health Canada will also continue to work closely with international regulators to review information as it becomes available on these very rare events, and will make further updates to the CPM or take other actions as needed.
Please refer to the following website in Health Canada for details:
http://hpr-rps.hres.ca/../summary-safety-review-detail.php?lang=en&linkID=SSR00266
In Hong Kong, the above product is not a registered pharmaceutical product. Related news was previously issued by various overseas drug regulatory authorities, and was posted on the Drug Office website since 10 Apr 2021, with the latest update posted on 27 Apr 2021.
Ends/Wednesday, May 5, 2021
Issued at HKT 16:00
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