Health Department defends benefits AstraZeneca vaccine outweigh potential risks

Hotline receives over 1,000 calls in one day

4 min
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Santa Coloma de GramenetThe temporary and precautionary suspension the AstraZeneca vaccine will not stop the vaccination campaign, because doses of Pfizer's and Moderna's will continue to be administered, according to the Secretary of Public Health, Josep Maria Argimon. Nevertheless, Argimon defended the European Medicines Agency (EMA), which on Tuesday re-emphasised that the benefits of AstraZeneca's vaccine outweigh its possible risks and adverse effects that it can generate. In this sense, Argimon stressed that the immobilisation of the vaccine has been decided by governments and not by the regulatory agency. "AstraZeneca has administered 17 million doses, 6 million in the European Union and 11 million in the United Kingdom, and 14 adverse events have been observed, 11 and 3 respectively," explained Argimon, who considers that this means less than one adverse effect per million cases and that it is "expected" even outside the context of vaccination.

Argimon insisted that the EMA has yet to determine whether the thromboses detected in some countries are due to a coincidence in time with the vaccination or if there is a cause-effect relationship. If the vaccines are found to have caused the thrombosis, he said, the EMA will have to assess whether the benefits outweigh the risks and develop strategies to lift the suspension and minimise these "infrequent risks. There is no drug or vaccine that does not have adverse effects. It is when evidence accumulates that events are observed and decisions are made," he said.

The head of pharmacovigilance at the Fundació Institut Català de Farmacologia, Gloria Cereza, explained that clinical trials of drugs provide fairly firm safety information to authorise a drug or vaccine. However, she reminded us that the complete toxicity profile of drugs has to be built up with the information obtained from the adverse effects that are reported as they are administered: "The aim of pharmacovigilance is to identify new risks in order to guarantee the benefit-risk ratio of the drug throughout its life on the market"

The expert explained that pharmacovigilance is based on focusing attention on spontaneous reporting -popularly known as yellow cards-, which collect individual cases of suspected adverse events linked to a specific drug. However, she insisted that these reports do not confirm a cause-effect relationship. "All countries collect this information, but the big system is European," he said. It is the European Medicines Agency (EMA) that has the last word. "A case in Spain is anecdotal, but different cases in other countries may be a sign that an in-depth analysis is required as now; the same happens with all drugs and vaccines," she summarised.

"Specific and rare" thrombosis

Cereza has insisted that the focus has only been placed on AstraZeneca, and not on Pfizer, despite the fact that quite isolated suspicions have also been documented, because the cerebral venous thrombosis that has led to the suspension of the AstraZeneca vaccine is "very specific and infrequent". Cerebral venous thromboses are thrombi or blood clots that impede or hinder blood flow in the venous system of the brain. It is a very rare condition - it accounts for less than 0.5% of cerebrovascular diseases in Spain - and affects somewhat more women and young people. In fact, some risk factors are oral contraceptives, pregnancy or the use of hormonal therapies. The most frequent symptom is an intense headache that starts suddenly and gets progressively worse.

"They are incapacitating headaches and more intense when getting out of bed," said Cereza. This episode is also usually accompanied by other signs similar to those of a stroke, such as loss of vision and strength, altered language or speech and episodes of confusion, as well as vomiting, epileptic seizures and, less frequently, cervical stiffness. "We have to be patient and wait for the EMA's opinion," the public health secretary insisted.

The Medical Emergency System's hotline, 061, has received a thousand calls related to the suspension of AstraZeneca's vaccination in a single day. However, the deputy director of Health Promotion, Carmen Cabezas, wanted to convey a message of tranquility and said that "today, with the information we have," AstraZeneca has more benefits than risks. She has claimed the good efficacy data in the United Kingdom, where it is being used on a massive scale and is already preventing hospitalisations and deaths.

Stagnation of the indicators

Argimon admitted some concern that the setback with the AstraZeneca vaccine could discourage people from getting vaccinated. "But we have to send the message that pharmacovigilance works," he said. If it were up to him, he said, he would also have adopted an attitude of caution as the EMA has done.

The Secretary of Public Health has also explained that the decline in infections in Catalonia has stagnated this week and is now almost imperceptible. "For a few days the decline has been very slow and we are getting slightly more positive antigen test results in people with symptoms compared to last week," warned the doctor. Although he has assured that Catalonia has not entered a phase of expansion, Argimon has anticipated that the rate of contagion or Rt, which measures contagion speed, will increase to 1, meaning it would no longer be receding.

Argimon admitted that the European context requires being more care than ever: he pointed out that France's cumulative incidence per 100,000 inhabitants is twice as high as Catalonia's and that Italy is already considering locking some areas down to control the pandemic. "We are giving air, but we have to contrast it with health and we are in an unstable situation," warned Argimon, who has insisted that people only travel with their coexistence bubble. Every day a thousand new cases are being reported and the healthcare situation in hospitals remains "fragile", with 432 people in ICU, warned Argimon