What is the incidence of thrombi caused by the AstraZeneca vaccine? These are the data in Spain and Europe


Publication: Thursday, April 8, 2021 10:14

On Wednesday, the European Medicines Agency (EMA) admitted a “possible link” between the AstraZeneca vaccine and a series of rare thrombi in some patients who received the injection. But the authorities insist precisely on the latter: the cases are so infrequent that, out of 100,000 punctures, only one records consequences of this type.

For the moment, different members of the EU have chosen to change their vaccination strategy and vary the minimum age with which to inoculate doses of the antidote developed by Oxford. Thus, Germany, Belgium, the Netherlands, Italy and Finland have established a range of 55 years (in the case of the Belgian country) and 60 years in the others. However, as the European body points out, the events by age group have not yet been confirmed, because each country has followed a different strategy.

In other words, “age, gender or medical history of bleeding disorders are not risk factors, as rare events are seen at all ages and in both men and women,” says the EMA. However, the screening carried out by the European pharmacovigilance, as well as by the Spanish pharmacovigilance, leaves a clear conclusion: it is extremely difficult for the injection to cause severe symptoms.

1 case of thrombus per 100,000 inoculations

According to EMA data, up to March 22, 86 cases of thrombi have been detected in the EU, with 18 deaths. By contrast, until April 4, there are 222 confirmed cases, but out of a total of 34 million people vaccinated. In other words, according to this incidence, there is only one case of thrombus per 100,000 bites (although in Europe, they note that this may vary in some countries, depending on their follow-up capacity).

In this sense, the Director General of the Spanish Agency for Medicines and Health Products, María Jesús Lamas, reported during the press conference after the Interterritorial Health Council on Wednesday that “the benefit-risk ratio of the vaccine stay positive “. In fact, in Spain cases can be counted on the fingers of one hand, also due to the low frequency of the vaccine compared to other countries. On some occasions, health has even ruled out such cases with the vaccine, as it cannot demonstrate causation.

Likewise, according to Lamas, “the vaccine’s interest has been shown to prevent COVID-19 and reduce hospitalizations and deaths”, although he defends the caution with which health authorities have acted so far. : “Despite the low frequency with which they occur, it is important to stress the importance of early diagnosis,” he stressed.

Spain, Belgium, Germany, the Netherlands … changes in the vaccination plan

Following the resolution of the European Medicines Agency, several countries have confirmed changes in their vaccination strategy. The first to do so on Wednesday was Belgium, which did not even wait until the end of the meeting between EU health ministers to determine that it would not put the Anglo-Swedish vaccine on until after 55 years. However, Germany had already chosen before to lock up groups from 60 years old, a decision to which Spain adhered (with a range of 60 to 65 years, although this Thursday a possible extension to 69 years is debated. ), like the Netherlands. , Finland or Italy.

For its part, the United Kingdom – so far the country which has administered the most injections of AstraZeneca – has confirmed that it will offer alternative vaccines to those of this company for those under 30. However, these people may decide to be vaccinated with AstraZeneca because its use is more widespread and the vaccination is faster. Meanwhile, British Prime Minister Boris Johnson has been frank about doubts about its effectiveness: “The vaccine is safe, effective and has already saved thousands of lives. Most people should accept it when offered.” he said on Wednesday.

In this way, in the absence of information in many cases (for example, to determine whether women are at greater risk from the vaccine, which, as we have pointed out, the EMA excludes for now) , a multitude of unknowns arise concerning the changes in the vaccination process.

In this sense, Carolina Darias indicated that she was considering the possibility of not administering the second dose to people vaccinated with AstraZeneca, because “the percentage of effectiveness is 70 percent only with a single dose”. Even so, he also offered another option, which would be to “see studies” that could “support the scientific evidence”. In any case, it is a decision which is “to be determined”, according to the leader “, who also stressed that confidence must be maintained in this injection, developed by professionals and subject to strong control processes.

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