Out of an extreme abundance of caution – and lack of numeracy, and disregard for a burgeoning third wave, and a tinge of hysteria – a handful of European countries have suspended their use of the Oxford-AstraZeneca vaccine for COVID-19. There have been 37 reported cases of blood clots out of roughly 17 million people vaccinated, an incidence rate (0.0002 per cent) that is actually lower than the rate at which blood clots are observed in the general population (0.1 per cent) and considerably lower than the risk of blood clots in patients hospitalized with COVID-19 (17 per cent, according to one meta-analysis). By these numbers, it would make more sense to tout AstraZeneca’s product as something that lowers the risk of blood clots than it does to suspend its use based on a tenuous correlation.
German investigators first flagged the vaccine because of reports of seven people who had suffered blood clots in the brain (specifically, in the veins that drain blood from the brain) after they received the AstraZeneca shot. The theory is that an immune reaction may have affected the formation of platelets and caused clumping, although that hypothesis is still very much under investigation. People develop blood clots all the time, after all, and with Germany’s vaccination program now averaging 240,000 doses a day, it could simply be a coincidence that those who would have suffered blood clots anyway also happened to be recently vaccinated. And even if causation is established – which is an enormous “if” – such a complication would still be incredibly rare. Indeed, based on incidence alone, everyday activities such as flying in a plane or taking hormonal birth control pills pose a far more significant risk of blood clots than taking the AstraZeneca vaccine. On Wednesday, the World Health Organization issued a statement supporting continued use of the shot, noting that the benefits outweigh the risks.
Yet a growing number of countries, including Germany, France, Italy, Spain, Austria, Sweden, Denmark, Norway, Iceland, Ireland and Latvia – have all suspended their use of the shot. Each country cites that aforementioned extreme abundance of caution, although the compounding pressure of one country after another deciding to suspend use of the vaccine has likely created something of a snowball effect. No government wants to be perceived as Europe’s odd one out (with the exception of Britain, which made a referendum out of the idea), or willing to risk the health of its citizens when there is even the most remote possibility of severe complications.
The irony is that this decision to tread carefully on AstraZeneca in effect creates harm by removing an important tool in controlling the growth of the third wave of COVID-19 in Europe. AstraZeneca’s vaccine previously accounted for about 15 per cent of inoculations carried out in the European Union, though the pace of vaccinations has already slowed down dramatically with AstraZeneca doses now sitting in refrigerators. And yet, while these countries now mull over what they’re supposed to do, people will continue to contract COVID-19 (more than 120,000 people in the EU on average each day, according to Our World in Data) and some of those people will develop complications – such as blood clots – and die.
Health officials, including Ireland’s deputy chief medical officer, have leaned on the “precautionary principle” to defend their decision to temporarily suspend the vaccine. But the precautionary principle is being misapplied if it’s being used against a tool proven to protect people against a potentially deadly virus because of an unproven theory of the harm it might cause to a far smaller percentage. It’s nonsense. Yet the damage has already been done, and if and when these countries resume the administration of AstraZeneca’s vaccine, they will surely encounter resistance from would-be recipients who would rather wait for an alternative vaccine than receive the recently-suspended-over-blood-clots one.
Canada, thankfully, has resisted the pressure to succumb to this snowball of suspensions, but its handling of AstraZeneca’s vaccine will likely breed its own form of hesitancy. Health Canada approved the vaccine for use in all adults on Feb. 26, though the National Advisory Committee on Immunization (NACI) recommended against its use in those over 65 three days later. Then, two weeks later, NACI changed its recommendation again, citing “new real-world data” (though real-world data previously existed) demonstrating AstraZeneca’s effectiveness in older adults – while still recommending those 65 and over be prioritized for other approved vaccines.
Canada pre-purchased millions of doses of seven different vaccine types, and Health Canada has approved four so far for the various provincial and territorial rollouts. All the drugs are fully effective in preventing serious illness and death, though some may do more than others to stop any symptomatic illness at all (which is where the efficacy rates cited below come in).
- Also known as: Comirnaty
- Approved on: Dec. 9, 2020
- Efficacy rate: 95 per cent with both doses in patients 16 and older, and 100 per cent in 12- to 15-year-olds
- Traits: Must be stored at -70 C, requiring specialized ultracold freezers. It is a new type of mRNA-based vaccine that gives the body a sample of the virus’s DNA to teach immune systems how to fight it. Health Canada has authorized it for use in people as young as 12.
- Also known as: SpikeVax
- Approved on: Dec. 23, 2020
- Efficacy rate: 94 per cent with both doses in patients 18 and older, and 100 per cent in 12- to 17-year-olds
- Traits: Like Pfizer’s vaccine, this one is mRNA-based, but it can be stored at -20 C. It’s approved for use in Canada for ages 12 and up.
- Also known as: Vaxzevria
- Approved on: Feb. 26, 2021
- Efficacy rate: 62 per cent two weeks after the second dose
- Traits: This comes in two versions approved for Canadian use, the kind made in Europe and the same drug made by a different process in India (where it is called Covishield). The National Advisory Committee on Immunization’s latest guidance is that its okay for people 30 and older to get it if they can’t or don’t want to wait for an mRNA vaccine, but to guard against the risk of a rare blood-clotting disorder, all provinces have stopped giving first doses of AstraZeneca.
- Also known as: Janssen
- Approved on: March 5, 2021
- Efficacy rate: 66 per cent two weeks after the single dose
- Traits: Unlike the other vaccines, this one comes in a single injection. NACI says it should be offered to Canadians 30 and older, but Health Canada paused distribution of the drug for now as it investigates inspection concerns at a Maryland facility where the active ingredient was made.
How many vaccine doses do I get?
All vaccines except Johnson & Johnson’s require two doses, though even for double-dose drugs, research suggests the first shots may give fairly strong protection. This has led health agencies to focus on getting first shots to as many people as possible, then delaying boosters by up to four months. To see how many doses your province or territory has administered so far, check our vaccine tracker for the latest numbers.
Certainly evolving with the science is a prudent strategy, but doing so without paying heed to the unintended consequences of invoking confusion and hesitancy will make the whole exercise moot. AstraZeneca’s vaccine has been branded – despite the evidence, probably irrevocably – as the one that causes blood clots and doesn’t work in older adults. Many people, understandably, will not want to take it. That will prolong the pandemic and ultimately cost lives.