How can you ensure the safety of Corona vaccines?

Washington: To verify the efficacy and safety of experimental vaccines against Covid-19, researchers are conducting clinical studies on tens of thousands of volunteers, generally distributed equally in two groups, one of which receives a placebo … This is the case with the experiments. on the “Pfizer / Biontech” and “Moderna” vaccines, which the developers have attributed to them. Very high efficacy.

The American group “Pfizer” is implementing and funding a clinical trial of its vaccine on 44,000 people in the United States, Brazil, South Africa and Turkey. These people participate on a voluntary basis and each receives two doses three weeks apart and are subject to periodic monitoring.

Moderna is being tested in collaboration with the National Institutes of Health, the highest public body for scientific research in the United States, which participates in the funding of the study and in the development of the vaccine, also given in two doses at four weeks. of distance. The experiment takes place in the United States exclusively with 300,000 volunteers.

Both. Even the nurse who injects the participants doesn’t know. A placebo is nothing more than a saline solution with no therapeutic effect.

Volunteers participating in the research continue their life normally: after receiving the injection, they return home and continue to work or study like others, with the need to follow the same preventive measures, both in terms of home quarantine and need to wear a muzzle.

Over the course of the days, a number of participants will naturally develop Covid-19, which will inevitably be known as participants must regularly inform researchers of any symptoms they have and any suspected cases are subject to diagnosis.

If the vaccine is effective, the number of cases recorded among participants who actually received the vaccine will be lower than in the second group whose members received a placebo vaccine.

The goal is to record a difference large enough to rule out the random hypothesis of these results. Researchers use statistical methods to obtain a predetermined minimum of certainty. Achieving a 100% efficacy rate means that no cases have been recorded in people who actually received the vaccine and many cases in the second group.

The primary goal of vaccines is not to prevent the transmission of Coronavirus infection, but rather to prevent people from contracting the Covid-19 disease caused by the virus. The vaccine is classified as highly effective if it can prevent Covid-19 infections in its dangerous forms.

This research stems from the idea that if a vaccine manages to protect people from disease, then this means achieving the desired goal in terms of public health, even with the continuous registration of people with the virus without any symptoms.

Both. The researchers only aim to record whether there is a “real-life” difference in Covid-19 infection rates between people who received the vaccine and those who did not.

In the absence of 100% effective treatment, it would be unethical to intentionally expose people to coronavirus, although researchers have already suggested doing so with healthy young people.

If the study was limited to following the conditions of 10 thousand people, of which 100 infected with Covid-19, how can one know the degree of effectiveness of the vaccine? Perhaps without the vaccine it would have scored a similar number of infections, or perhaps double or ten times as many.

Therefore, the only way to determine efficacy is to compare the results with those recorded in a parallel number of people who did not receive the vaccine, i.e. the alternative group.

With the many samples of tens of thousands of people chosen to reflect a representative image of the population, it will be almost certain that the two groups will guarantee the same diversity in terms of personality traits and behaviors, allowing them to confront each other.

There is no reason for young participants in one group, for example, to refuse to wear a mask without the others in the second group, especially since people don’t know whether they have received the real vaccine or placebo.

Data analysis does not take place directly in the hands of companies, but rather through committees of independent experts called the “Data and Safety Monitoring Board” (“DSMB” or Data and Safety Supervision Committees). The names of the participants in these committees are kept confidential to protect them from any political or similar pressure.

In Pfizer’s case, the oversight committee is made up of five members. With the Moderna and AstraZeneca / Oxford and Johnson & Johnson vaccines, a single independent expert panel was formed by the National Institutes of Health with between ten and fifteen members, according to “Kaiser Health News”.

These committees reveal, at fixed intervals established in the experimental protocols, the data collected to find out which groups the participants belong to. Committee members can inform the developer of their results if they are positive, and the company can later use the data to decide in its light whether it will require permission to put the vaccine on the market.

In addition to effectiveness, the committees also closely monitor the issue of safety, analyzing the severity of side effects and their frequency, a critical factor in deciding whether or not to allow the product to be placed on the market.

“Pfizer” announced that it had registered 170 cases of Covid-19 in the seven days following the second dose of the vaccine, which is a small number compared to the total number of participants (44,000).

But statistically, this result is sufficient. In fact, 162 of these infected people were in the group that received a placebo vaccine and 8 in the group that actually received the vaccine. The difference is so great that it is highly unlikely that it is a coincidence.

95% effectiveness, concluded by researchers working to develop the vaccine, means that people who receive the vaccine have a 95% lower risk of developing Covid-19 disease than those who do not receive the vaccine.

Here lies a big ethical problem. Usually, when the efficacy of a drug or vaccine has been validated, participants who have received a placebo are informed of the truth of the matter and offer to receive the actual product if they wish.

In all cases, nothing prevents suspected participants from independently going to the pharmacy to receive the vaccine.

But the problem is that the trials are designed to last two years or more, in order to determine the duration of the protection provided by the vaccine and to monitor the emergence of long-term side effects.

To date, the health authorities, in response to questions from manufacturers, have not issued any recommendations to solve this problem.