There is no evidence that AstraZeneca causes blood clots, but why is there anxiety?

According to the expert, some concerns about the new vaccine are understandable: any suspected adverse reactions should be investigated.

“But now we have to think not only fast, but also slowly. It is necessary to resist the temptation to look for causal connections where they may or may not exist,” emphasizes D. Spegelegelter.

How many cases would there be without vaccination?

Ronan Glynn, deputy chief medical officer for Ireland, one of the countries that temporarily suspended the vaccine developed by researchers at AstraZeneca and the University of Oxford, has tried to emphasize that there is no evidence that this vaccine causes blood clots.

And D.Spiegelhalter adds that people really like to link different and simply unrelated events. For example, we wash the car and the next day a bird is added to the hood, as is typical.

There are more serious threads that we build. For example, a child who is vaccinated with the MMR vaccine is diagnosed with autism; there are people who think, without reason, that it is related.

Now that a small group of people who have been vaccinated with AstraZeneca have blood clots, there is growing concern about whether the vaccine can be blamed.

But when the European Medicines Agency announces that 30 thromboembolic incidents have been reported in about 5 million cases. vaccines, the most important question is: how many such cases would there be even without vaccination? ”Writes D.Spiegelhalter.

It is offered to calculate. Deep vein thrombosis is diagnosed annually in an average of one in every 1,000 patients. people. For older people, the numbers are likely to be slightly higher.

When the European Medicines Agency announces that 30 thromboembolic incidents have been reported in about 5 million cases. vaccines, the more important question is: how many of these cases would occur even without vaccination?

According to such indicators, such thrombosis would be detected in more than 5 thousand. people per year – from 5 million. vaccinated people. In other words, at least 100 people a week. For this reason alone, it is not surprising that 30 reports of blood clotting incidents have been received.

The research data is clear

According to a researcher at the University of Cambridge, it would be much easier if there were a large group of people with the same composition as the vaccinated AstraZeneca, but whose members were not vaccinated.

After all, it would show how many serious incidents would be recorded in the case of people who had not even been vaccinated. “In fact, that group of people really is,” Spegelhalter said.

In post-approval clinical trials of AstraZeneca in the UK, volunteers received either an active vaccine or a placebo. Then all study participants were asked to report any side effects they experienced.

“The most important thing is that nobody knew if they had received a real vaccine or an inert injection. And by comparing the indicators of both groups, we can see how many ‘reactions’ were determined by active vaccination, how many were related to the vaccination process and how many would have occurred in any case ”, explains D. Spegelhalter.

What are the results? 38 percent of volunteers who received the vaccine itself reported some side effects. But even 28% of the body reported some reaction. those who received placebo.

There is no evidence that vaccination with AstraZeneca increases the risk of serious side effects.

This shows that, collectively, about two-thirds of the reported side effects were due to the vaccination process itself and not to the particular vaccine.

Of the more than 24 thousand. less than 1% of study participants. reported a serious reaction. And of these 168 people, more than half received a placebo rather than an active vaccine.

“Therefore, there is no evidence that vaccination with AstraZeneca increases the risk. By the way, the test results for the Pfizer vaccine are the same,” says D. Spiegelhalter.

AstraZeneca itself reported that 15 cases of deep vein thrombosis and 22 cases of pulmonary embolism had been reported in vaccinated people. According to the company, this figure is “much lower than would be expected under natural conditions in the general population” in terms of total injections.

‘Extremely safe’ vaccines

Clearly, clinical trials are usually short, involve a limited number of people, and are healthy. Therefore, there is a clear need to collect real data already during vaccination.

In the UK, reports of side effects are recorded using a ‘yellow card’ system. By February 28, around 54 thousand. Those messages were related to the specific AstraZeneca vaccine, which was administered in a dose of approximately 10 million at that time.

Pfizer’s performance is slightly better, but basically the statistics are as follows: For both vaccines, side effects have been reported after 3 to 6 doses per thousand, which means there have been even more such reports in clinical trials.

In addition, many of the reported reactions are not serious: patients complain of pain in the hands, headache, fatigue, fever. All these symptoms disappear after a few days; only allergic reactions are considered a more serious problem.

“So far these vaccines are extremely safe. In fact, it’s even strange that we don’t hear more stories about side effects.

We hope that this information reaches those who still have doubts, be it about the misinformation about the harm of vaccines or the comments of some European politicians, ”writes the Cambridge expert.