Green light for AstraZeneca: science has won

Four thousand people. In Tuscany alone, after the stop of a batch of AstraZeneca vaccines for adverse reactions, four thousand people in three days canceled their appointment with the vaccinaction against Covid-19. Among these are young and old, worried parents and “vulnerable” subjects, ordinary people with the common factor of having found themselves at the mercy of doubt. The total, temporary suspension by AIFA (Italian Medicines Agency) of this vaccine, thus stopping each AstraZeneca batch as a precaution, pending the official response from the EMA (European Medicines Agency), has in fact fueled further panic among the citizens, blowing on those doubts that someone already had towards something scientifically safe.

So let’s clarify with some simple calculations.

According to the Italian Association of Epidemiology, in the general population between 35 and 70 years of age, about 80 cases of “DVT” (deep vein thrombosis) per 100,000 people are expected in one year. Statistically we are therefore talking about 1.5 / 2 cases expected per week, that is 6/8 cases every 100,000 people in a month. Considering that there were over 800,000 people vaccinated with AstraZeneca (including those belonging to the armed and police forces, and those concerning school staff), if there was a real link between the cases of thrombosis verified in recent days and the vaccine itself , we would have registered more than 42 hospital admissions for “DVT”, which in fact did not happen since 18 out of 20 million were vaccinated (twenty million!).

It is therefore right to return the ball to the center in the field of rationality as soon as possible, remembering that these cases occur due to the normal incidence of the disease. All the more so now that the EMA safety committee has confirmed: AstraZeneca is safe and effective, stop the precautionary suspension and immediate green light with the next vaccinations, with the approval already arrived from Mario Draghi. “A clear scientific conclusion”, the executive director of the Emer Cooke committee defined it: “This is a safe and effective vaccine and its benefits and the protection of people from Covid-19 and associated risks and hospitalizations outweigh the possible risks”.

For this in scientific research we must not confuse the two levels “correlation” and “causality”: the first refers to a relationship between two or more variables that change together (if one increases the other does, or if one increases the other can decrease, but there is still a link between the two), the second instead refers to a relationship between two or more variables where one actually causes the other, but if three criteria are met (the variables must be correlated, one variable must precede the other and finally a third variable must not cause any change in the other two).

Simply put: correlation is not necessarily an indication of causality, because “chance” could have put a hand in it without any relationship, or something hidden that escapes us and has not been considered (the third “confounding variable”) could push us off track that we cannot make an objective evaluation. This, of course, can be understood through analysis, experiments, tests, statistics… in a rigorous way, and not through chatter and bar arguments, without any scientific basis. This is why we all have a great commitment to social responsibility, in this delicate phase, to carry on.

While on the one hand the media themselves should contribute to offering a clear and simplified narrative, within everyone’s reach, through data and numbers that are easily understood even by those who are not experts on the subject, on the other, those citizens who are aware of the situation not to fuel further wars and discussions, but to “accompany” this delicate understanding becoming the spokesperson for a reassuring message, as far as possible and in their capacity. On the other hand, anxiety and panic also spread like any contagion.

We are the first to try to dispel any doubt, any fear, any form of resistance in those close to us, in this decisive phase, who could change their minds and withdraw from vaccination, allowing themselves to be overwhelmed by the state of uncertainty. We try not to leverage the confusion of others to incite yet another witch hunt, because the fear combined with the pain accumulated in recent months now play the worst joke, that of surrender. And we can’t allow it. We need understanding and listening, sensitivity and patience, but above all we need to make room for science and the results we are obtaining: loudly, louder than skepticism, and surer than any unfounded doubt.