Grandparents killed in wrong-way crash on Hwy. 401 identified
A 60-year-old man and a 55-year-old woman killed in a wrong-way crash on Highway 401 earlier this week have been identified by the Consulate General of India in Toronto.
Scientists in the U.K. believe they have discovered the reason why some people experienced the very rare side-effect of blood clots after receiving the AstraZeneca COVID-19 vaccine.
The findings, published in the journal Science Advances on Wednesday, reveal that a protein found in blood is drawn to a component of the vaccine, which triggers a reaction from the body’s immune system that can result in clots.
The AstraZeneca vaccine, like other viral vector vaccines, uses a safe virus as a “host” to deliver genetic information about the COVID-19 spike protein to the vaccine recipient's cells so that they can build an immune response and create antibodies.
The AstraZeneca COVID-19 vaccine uses a cold virus from a chimpanzee, also known as a chimpanzee adenovirus, as the delivery system. This is because it cannot make humans sick – and, because they have not been exposed to it before, they will not have antibodies against it.
Viral vector vaccines modify the delivery virus so that it cannot spread, they simply delivers the instructions for the body’s cells.
By analyzing the chimpanzee adenovirus used by AstraZeneca with cryo-electron microscopy, which allows for molecular-level details to be seen, researchers found that the adenovirus attracts the blood protein known as “platelet factor 4” to it.
Cryo-electron microscopy involves flash-freezing the study subject and then bombarding them with electrons to produce microscope images of individual molecules. Those are then used to reconstruct the structure of the subject in minute detail.
The cryo-electron microscopy image of the chimpanzee adenovirus, which is less than 100 nanometres across, that delivers the Oxford-AstraZeneca vaccine. (Science Advances Journal)
The cryo-electron microscopy image of the chimpanzee adenovirus which delivers the Oxford-AstraZeneca vaccine. (Science Advances Journal)
Platelet factor 4 is implicated in the origins of another clotting event called heparin-induced thrombocytopenia (HIT), which causes changes to the blood that may cause a clot to form in the blood vessels.
Researchers posit that the body begins to attack the platelets that are attached to the adenovirus, after mistaking it as part of the foreign virus. Then, when antibodies are released into the bloodstream to attack, they clump together with the platelet factor 4 and can form a dangerous blood clot known as vaccine-induced thrombotic thrombocytopenia or VITT.
Because that sequence of events in the body is so specific, it may explain why the development of blood clots after receiving the vaccine is such a rare phenomenon.
The U.K. findings echo a Canadian study conducted by researchers at McMaster University in Hamilton, Ont., and published this July in the scientific journal Nature.
In the Canadian study, researchers analyzed blood samples from five patients with VITT and compared them to blood samples of 10 patients with HIT and 10 samples from healthy individuals.
Looking at the amino acids of the interaction between the VITT antibodies and platelet factor 4 protein, researchers found eight specific amino acids on the platelet protein that were identical to the binding site of HIT, which they believe could explain the similar patterns in how the blood clots form after vaccination.
However the U.K. study was able to render the highest resolution of the adenovirus used in the AstraZeneca COVID-19 vaccine to date, allowing them to better understand its primary cell attachment proteins and its structure.
VITT has been linked to at least one death in Canada after an Ontario man received the AstraZeneca vaccine in May, and to 73 deaths out of close to 50 million doses of AstraZeneca administered in the U.K.
The Public Health Agency of Canada’s National Advisory Committee of Immunization stopped recommending AstraZeneca’s COVID-19 vaccine as a second dose option after some Canadian recipients reported blood clots in the spring of 2021.
Researchers in the U.K. hope their study findings can be used to improve future vaccines and reduce the risk of blood clots.
-----
With files from CTVNews.ca writer Brooklyn Neustaeter
A 60-year-old man and a 55-year-old woman killed in a wrong-way crash on Highway 401 earlier this week have been identified by the Consulate General of India in Toronto.
Three people have been arrested and charged in the killing of B.C. Sikh activist Hardeep Singh Nijjar – as authorities continue investigating potential connections to the Indian government.
Pius Suter scored with 1:39 left and the Vancouver Canucks advanced to the second round of the NHL playoffs with a 1-0 victory over the Nashville Predators on Friday night in Game 6.
TD Bank Group could be hit with more severe penalties than previously expected, says a banking analyst after a report that the investigation it faces in the U.S. is tied to laundering illicit fentanyl profits.
A Quebec man who pleaded guilty to threatening Prime Minister Justin Trudeau and Premier François Legault has been sentenced to 20 months in jail.
RCMP say human remains found in a rural area in central Saskatchewan may have been there for a decade or more.
A source close to singer Britney Spears tells CNN that the pop star is 'home and safe' after she had a 'major fight' with her boyfriend on Wednesday night at the Chateau Marmont in West Hollywood.
As Wegovy becomes available to Canadians starting Monday, a medical expert is cautioning patients wanting to use the drug to lose weight that no medication is a ''magic bullet,' and the new medication is meant particularly for people who meet certain criteria related to obesity and weight.
Drew Carey took over as host of 'The Price Is Right' and hopes he’s there for life. 'I'm not going anywhere,' he told 'Entertainment Tonight' of the job he took over from longtime host Bob Barker in 2007.
Alberta Ballet's double-bill production of 'Der Wolf' and 'The Rite of Spring' marks not only its final show of the season, but the last production for twin sisters Alexandra and Jennifer Gibson.
A British Columbia mayor has been censured by city council – stripping him of his travel and lobbying budgets and removing him from city committees – for allegedly distributing a book that questions the history of Indigenous residential schools in Canada.
Three men in Quebec from the same family have fathered more than 600 children.
A group of SaskPower workers recently received special recognition at the legislature – for their efforts in repairing one of Saskatchewan's largest power plants after it was knocked offline for months following a serious flood last summer.
A police officer on Montreal's South Shore anonymously donated a kidney that wound up drastically changing the life of a schoolteacher living on dialysis.
Since 1932, Montreal's Henri Henri has been filled to the brim with every possible kind of hat, from newsboy caps to feathered fedoras.
Police in Oak Bay, B.C., had to close a stretch of road Sunday to help an elephant seal named Emerson get safely back into the water.
Out of more than 9,000 entries from over 2,000 breweries in 50 countries, a handful of B.C. brews landed on the podium at the World Beer Cup this week.
Raneem, 10, lives with a neurological condition and liver disease and needs Cholbam, a medication, for a longer and healthier life.