Why Covishield is ‘safe’ despite the blood clot scare in Europe
Cases Of Blood Clots Among Vaccinated People Are No More Common Than In The General Population, Say Experts
Abhilash.Gaur@timesgroup.com
17.03.2021
Serum Institute’s Covishield is India’s main Covid vaccine. In the West, it is known as the ‘Oxford’ or ‘AstraZeneca’ vaccine. Over the past few days, 11 European countries, including Germany, France, Ireland, Norway, Denmark and the Netherlands, have suspended its use over fears it causes blood clots. There’s no proof yet, but as country after country hits pause, you might wonder whether Covishield is safe for you. Should you still keep your vaccine date?
The short answer is: yes. The problem — if it can be linked to the Oxford vaccine at all — has affected only 37 of the 1.7 crore Europeans vaccinated with it, says BBC health correspondent Nick Triggle. That would be roughly equal to 2,800 cases among 130 crore Indians. Considering the coronavirus has killed about 1.6 lakh Indians in the past year, the vaccine’s unproven side effects should be the least of our worries.
‘No increase in cases’
The Guardian’s health editor Sarah Boseley points out the problems this vaccine is suspected to cause are equally prevalent among people who have not taken it. “The numbers of blood clots and thrombocytopenia cases in people who have been vaccinated is no higher than in the population that has not received the jab.”
Thrombocytopenia is a condition in which the body does not make enough platelets, so the risk of excessive bleeding increases.
In an opinion piece for The Guardian, British statistician Sir David Spiegelhalter says, “It is not at all surprising that there have been 30 reports.” After all, ‘deep vein thrombosis’ – the formation of blood clots inside veins – is a relatively common problem, affecting 1 out of every 1,000 people each year. “Probably more in the older population being vaccinated.”
Even without the Oxford shot, 17,000 of the 1.7 crore vaccinated Europeans would probably have suffered clots in a year. That’s 47 every day. Why the fuss over 37 cases, spread over several weeks?
European governments are acting out of “an abundance of caution,” says Boseley. Triggle agrees the decision “has been made on the basis of the precautionary principle.” But when a pandemic is killing thousands of people every day, “it is an approach which can sometimes do more harm than good.”
‘Vaccines don’t cause clots’
A Johns Hopkins University scientist tells The New York Times, “Vaccines have not been shown to cause blood clots.” Another expert says the factors that increase the risk of clots are more common in the high-risk populations that are being vaccinated first. So, it’s possible that the vaccine is not to blame for the clots.
However, some vaccines – including the measles/mumps/rubella (MMR) shot given to children – can temporarily lower the level of platelets. And lower platelet levels “have been reported in small numbers of patients receiving the Moderna, Pfizer-BioNTech and Astra-Zeneca vaccines.”
For now, though, even the International Society on Thrombosis and Haemostasis says a few cases among lakhs of vaccinated people do not suggest a direct link, and “people with a history of blood clots or taking blood-thinning drugs should go and get their vaccination,” Boseley writes in The Guardian.
More vaccines coming
While doubts about side effects have clouded the vaccine rollout in Europe, Science Magazine has good news for poorer countries. Last year, the US, UK, Canada and other rich countries reserved many times more vaccines than they needed. As they wrap up vaccinations over the next few months, they will be left with a glut of unused vaccines.
Australia, Mexico, Japan, Canada, the US, Italy, the UK, Germany, Poland, Spain and France will have enough spare shots to fully vaccinate 2.9 billion more people. These vaccines would be “enough to immunise everyone in the many poorer nations that lack any secured Covid-19 vaccine.”
Meanwhile, Bloomberg reports, 8 new Covid vaccines could be launched by the year-end. Some of them are based on safer technologies and can be given without a syringe. So, they might be better suited to pregnant women and other groups, it quotes WHO chief scientist Soumya Swaminathan.
