the astrazeneca and johnson & johnson (j&j) vaccines have faced scrutiny and apprehension from the public and governments with some countries going as far as pausing their use altogether. j&j use has been paused in the united states, the european union and south africa while denmark became the first country to completely stop using the astrazeneca vaccine.
“get whatever vaccine is available to you. it’s that simple. the longer you wait to get vaccinated, the longer you’re not protected,” dr. supriya sharma, health canada’s chief medical adviser told reporters last week. “we know the risks of getting these side effects from the vaccine are very rare.”
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risk versus reward
but what are the risks, exactly? six people experienced blood clotting in the u.s. among 6.8 million doses of the j&j vaccine. the astrazeneca shot has been given more than 20 million times in the u.k., with the chances of developing clots from that vaccine are around one in 250,000. these are exceedingly long odds, especially when you consider how common blood clots are in everyday life.
for example, experiencing a blood clot after surgery is common in orthopedic surgery. pregnant women have about a one in 500 chance of developing a blood clot, while women on birth control are at about a one in 1,600 risk . but for people hospitalized with covid-19 these odds grow to a whopping one chance in five that they will suffer from a blood clot.
in fact, according to a recent study in the bmj, the virus is “associated with a far greater risk of cerebral venous thrombosis than the vaccinations that protect against it.”
the vaccine blood clot
cerebral venous sinus thrombosis (cvst) is actually a rare form of stroke and is not a clot itself.
according to johns hopkins
medicine, cvst “occurs when a blood clot forms in the brain’s venous sinuses. this prevents blood from draining out of the brain. as a result, blood cells may break and leak blood into the brain tissues, forming a hemorrhage.”
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in general, there are two kinds of blood clots — arterial clots and venous clots. both can occur in the brain, abdomen, legs, arms, lungs or heart, causing serious health problems such as a heart attack, stroke or a pulmonary embolism .
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nick beare is a writer with healthing.ca .