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“Confidence in the safety and efficacy of the vaccines we have approved is of paramount importance. The final decision of the EMA will be given on Thursday [18 marzo 2021]”. This is more or less said by the director of the European Medicines Agency (EMA), Emer Cooke.
We are therefore awaiting a judgment on the possible association (there is no reason to speak of a correlation, therefore of a clear cause-effect relationship) between the use of one of the vaccines currently available in Italy and events of thromboembolism.
We must be very careful not to confuse these two situations: it is not for nothing that the Latins who knew how to use words well, differentiated “post-hoc”, this one thing that temporally follows another randomly, and “propter hoc”, which used when, on the other hand, the relationship between an action and the subsequent reaction was clear.
For this reason it is hoped that the administration of the Astra-Zeneca vaccine can be restarted as soon as possible: the information is being checked, and then – hopefully – restart. But on the occasion, it is also possible to take stock of the vaccines currently available and those that should arrive shortly, allowing us to protect an increasingly large number of people from infection and preserve us from the serious forms of Covid-19, which endanger the maintenance of health facilities.
There is no Sars-CoV-2 virus in vaccines
First of all we need to clear the field of a “fake news” that is still heard: the virus is not present in the vaccines that are administered. To ensure that the body’s defense system produces a sufficient quantity of antibodies capable of reacting if Sars-CoV-2 were to infect a person, in fact, currently two ways are used in vaccines on the market in Italy.
Preparations that contain m-RNA (i.e. messenger RNA) in practice provide the instructions for producing antibodies and vaccines do something similar, such as the Astra-Zeneca one, which instead are based on a carrier virus, which presents Sars-CoV-2 virus antigens. In practice, the adenovirus that is unable to replicate is “loaded” with information relating to the S proteins (the spikes of the virus), and therefore becomes a kind of postman who simply leaves a message. It is the immune system, which must receive it, starting on the basis of this information to produce antibodies.
The Johnson & Johnson vaccine, to be administered only once, ignoring any future recalls, which is expected to arrive in Italy in the coming weeks, is based on the same principle. It is based on a virus that acts as a vector. And in the same way, the Russian Sputnik V vaccine was also studied, which involves two administrations and above all uses two different adenoviruses as “postmen”.
To be fair, among the different types of vaccines used or being studied, there are also preparations that use inactivated Sars-CoV-2 viruses (one is produced in China), but at the moment they are not available in Italy. It must be said, however, that the efficacy profile of the various vaccines available is extremely high, as evidenced by the decline in new cases of hospitalization in countries that have carried out mass immunization, with particular attention to the weakest sections of the population.
The importance of safety
Similarly, also on the safety front there is extremely reassuring information, now linked to an experience of millions of doses administered, also for the Astra-Zeneca vaccine. We are obviously not talking about temporary side effects, such as pain at the injection site, a few lines of fever and malaise, but serious adverse events.
Above all, it is very clear that the risks associated with vaccination they are vastly lower than the risks associated with the disease. But then why did we stop?
In Germany, seven cases of a rare form of cerebral venous sinus thrombosis with decreased platelet count have been reported, appearing in a time close to that of the administration of the vaccine. We recall that safety, in any case, is fundamental in evaluating the risk-benefit profile of a vaccine, as well as of all drugs. For the vaccine, attention is maximum. Because? Because it must be done not to cure, but to protect, to people who do not have specific problems. Therefore it cannot and should in no way be suspected of having serious adverse effects.
The attention on this aspect is obviously very high and can help explain the precautionary and temporary stop to the administration of the Astra-Zeneca vaccine, on the basis of the finding of specific forms of thromboembolism observed in Germany. On the other hand, when evaluating drugs, such as anticancer drugs, obviously attention is always paid to the safety profile of use but a worse risk profile can be “tolerated”, since these drugs can help a person with a serious illness. for this reason, safety must be absolute for a vaccine.
Once proven the lack of correlation between the administration of the vaccine against Sars-CoV-and serious events, as is already emerging from the autopsies on some suspected cases in Italy, we can start again by making the most of all the weapons we have to protect ourselves against the pandemic coronavirus.
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