Saturday, November 23

What is the nocebo effect, the cause of 76% of adverse events of the Covid vaccine

La predisposición a las vacunas es un efecto para desarrollar algún efecto secundario a las mismas.
The predisposition to vaccines is an effect to develop some secondary effect to them.

Photo: Alberto Valdes / EFE

Health experts worldwide agree that one of the great “weapons” to combat the Covid pandemic is vaccination, That is why they urge the population to get vaccinated in order to protect themselves and others, ensuring that all vaccines approved by official authorities are safe and effective .

However, there is a big anti-vaccine movement that have caused thousands of people around the world to refuse to be immunized against the coronavirus, mainly arguing the speed with which they were made and above all because they know of cases of people who have suffered irreversible side effects after apply them or, they died of Covid despite being vaccinated.

It is true that, unfortunately, there were those who could not overcome the disease despite being already with full doses or boosters of vaccines or, for having developed some n health problem related to any side effect of the vaccines; however, one study found the main reason for the adverse events generally attributed to anticovid vaccines.

JAMA Network Open recently published a study conducted by scientists at Beth Israel Deaconess Medical Center in the United States, who analyzed data from 12 clinical trials of vaccines against Covid and discovered that the so-called “nocebo effect” ( which is the opposite of the well-known placebo effect) accounted for about 76% of all common adverse reactions after the first dose and almost 52% after the second dose.

This finding suggests that a considerable proportion of mild side effects of vaccines (headaches, short-term fatigue and arm pain) are not caused precisely by components of the vaccine, but rather by other factors that generate the nocebo response, such as anxiety, expectations, as well as erroneously attributing various ailments to having received the puncture.

The placebo effect is a well-known phenomenon that improves the physical or mental health of a person after taking a treatment without pharmacological therapeutic benefit, for example, a sugar pill or a syringe filled with saline solution. While the exact biological, psychological, and genetic underpinnings of the placebo effect are not well understood, some theories point to expectations as the primary cause, while others argue that unconscious factors embedded in the doctor-patient relationship automatically reduce the volume of symptoms.

But sometimes the placebo effect can also cause harm: it is the nocebo effect, which occurs when a person experiences unpleasant side effects after taking a treatment without pharmacological effects. That is to say, that same sugar pill that causes nausea, or that syringe filled with saline solution that produces fatigue.

“Collect the systematic evidence with regarding these nocebo responses in vaccine trials is important for vaccination against Covid-19 in around the world, especially since concerns about side effects are reported to be a reason not to get vaccinated,” explained Julia W. Haas, one of the lead authors of that study.

In the research in which the responses to vaccines were analyzed, both in the first and second doses of more than 22,000 people, found that these noxious effects occurred much more with the first vaccine than with the second. While the reason for this relative decrease in nocebo effects cannot be confirmed, the researchers believe that the higher rate of adverse events in the first-time vaccine group may have led participants to anticipate more the second time.

“The evidence suggests that this type of information can cause people to mistakenly attribute common daily sensations as derived from the vaccine or cause anxiety and worry that make people very alert to bodily feelings about adverse events”, added Haas.

Researchers believe that it is necessary to inform the population regarding the adverse effects that vaccines could have, since finally, the medicine is builds trust and may also help reduce concerns about vaccination.

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