Less than a week after its first administrations in France, the AstraZeneca vaccine arouses « surprise » see ” worry “. Reserved for health and medico-social professionals under the age of 65, the product from the Anglo-Swedish group was the subject of 149 pharmacovigilance declarations in five days and 10,000 injections.
In his last point position, published on February 11, the National Medicines Safety Agency (ANSM) mentions “Flu-like symptoms often of strong intensity” constituting a “Potential signal”. The World Health Organization (WHO) defining the « signal » like a “Relationship between a drug and an unknown or undocumented effect”.
Hospitals suspend their vaccination
“We are not surprised by the side effect itself – high fevers were frequently reported in clinical trials – but by its severity and the impact on those vaccinated”, describes Aurélie Grandvuillemin, vice-president of the association of regional pharmacovigilance centers (CRPV), responsible for compiling and verifying declarations. Fever, headache and fatigue: the symptoms are such that caregivers have been off work for a day.
Infectious disease specialist and coordinator of the Cochin-Pasteur vaccinology center, Odile Launey did not expect these Side effects of a “Surprising intensity” : “At no time was it said that there would be an impact on the ability to go to work as is the case today. “ From February 11, in the West, the hospitals of Brest, Morlaix and Saint-Lô suspended the injection of AstraZeneca serum so that post-vaccination work stoppages do not disrupt care. On the same day, the ANSM recommended for this purpose to “To vaccinate in a phased manner the staff of the same service”.
No massive reports abroad
These effects are all the more surprising since no other country has reported such inconvenience. Not even the UK, where over three million doses have been administered. By reporting the package of declarations to the European Medicines Agency, the ANSM will know if states have experienced similar mishaps without reporting them spontaneously.
It remains to explain the intensity of side effects noted in France but gone unnoticed during clinical trials. Several hypotheses are already mentioned. Some tick on the average age – 34 years – of people at the origin of pharmacovigilance declarations. ” We know that vaccines in general are more reactogenic in younger people, explains pharmacist Aurélie Grandvuillemin. For messenger RNA sera [Pfizer-BioNTech et Moderna], studies showed that older people had less local reactions. But AstraZeneca is a vaccine with a different platform [à base d’adénovirus]… »
Link between side effects and contamination?
Another characteristic of the reports: their place of work, health centers, which are particularly exposed to the epidemic. However, among the arguments allowing it to recommend a single dose for former Covid-19 patients, the High Authority for Health (HAS) mentions in its latest opinion a “Systemic reactogenicity” (fever, fatigue …) more pronounced in those already affected by SARS-CoV-2.
Have the cases of intense side effects been previously contaminated? “It could be an explanation, confirms Daniel Floret, vice-president of the technical committee on vaccinations at the HAS. In the case of caregivers, it is possible that a high proportion of them were affected [par le Covid-19] and now face more frequent side effects. “ “It is a possible avenue of explanation that we try to document as much as possible”, says Aurélie Grandvuillemin.
“The benefit / risk balance is not called into question”
But for the head of the pharmacovigilance center of the Dijon University Hospital, the first agitated French week of AstraZeneca does not threaten ” absolutely not “ its place in the vaccination campaign: “Adverse effects are of course temporarily disabling, but they will not call into question the benefit / risk balance. No alarming clinical evidence has been reported to us. “
Difficult, also, for the health authorities to give up so quickly one of the only three vaccines authorized for the moment and whose doses are sent in dropper. “If we have the possibility of vaccinating with other references which cause fewer problems, we will potentially call into question [AstraZeneca], warns Odile Launay. But that’s not the case at the moment. In a time of shortage, it will be difficult to do without this vaccine. We really need it. “