Coronavirus vaccines: what is an effi …

Moderna announced that its vaccine is 94.5% effective in the fight against the coronavirus and that to date, volunteers who receive its doses have not experienced any adverse effects. With this, the US company joined statements from Pfizer and the Gamaleya Center last week, claiming that their candidates were 90% and 92% effective, respectively. The goal? Get regulatory approval as soon as possible. “This is very good news, it is very promising data. Studies, of course, must continue; they will become more complex as volunteers become infected with covid. Only in this way is it possible to complete the mid-phase trials. There is still some time for the vaccines to arrive and a massive campaign is being waged, so in the meantime we cannot relax care in any way, ”he said. Daniela hozbor, biochemist and principal researcher at Conicet at the Institute of Biotechnology and Molecular Biology of La Plata.

Moderna’s statement reported the following: “The primary endpoint of the Phase 3 study is based on the analysis of confirmed and judged COVID-19 cases starting two weeks after the second dose of vaccine.” : “This first interim analysis was based on 95 cases, of which 90 cases of covid-19 were observed in the placebo group versus 5 cases observed in the mRNA-1273 group (which received the vaccine), resulting in a point estimate of vaccine efficacy of 94.5%“. To clarify: 90 people in the placebo group who participated in the tests contracted a coronavirus, compared to only 5 in the vaccinated group. The study, called COVE, was carried out according to the parameters stipulated by the National Institute of Allergies and Infectious Diseases (Niaid) and the United States Institutes of Health, which are part of the National Institutes of Health (NIH) and the Biomedical Institute.

What does a Conicet reference think of the communication of the preliminary analyzes carried out by Pfizer, the Gamaleya Center and Moderna? “These values ​​were determined in the intermediate stages of phase 3, which will last between 6 months and 2 years depending on the case. What the labs do is check how the vaccine works to protect us from disease. In this sense, they include a control group that receives a placebo and another vaccinated with the active substance, ”explains Hozbor. Then complete: “In any case, what we see is that most coronavirus patients are registered in the volunteer population not immunized with the drug “.

If this percentage of efficacy was kept above 90% and could be corroborated at the end of the testing phase in the thousands of volunteers, this would be excellent news as it would therefore imply a robust immune response. In fact, experts predicted that An efficacy of 60% or 70% for the coronavirus would be sufficient, if we take into account the emergency scenario in which all countries find themselves due to the pandemic.

In this sense, to understand whether values ​​above 90% efficiency are adequate, from Hozbor’s point of view, it is essential to check it in light of what is happening with the vaccines that make up the mandatory schedule in Argentina. “Most are between 80, 90 and 95%. In fact, there are some, like the flu, that are 60% effective. What should not be forgotten is that these technologies not only have a beneficial effect on the person who receives them, but also generate what is called “collective immunity” “, he emphasizes. Under this premise, he continues his reasoning: “This means that while not all people get the vaccine, if we reach these percentages the spread of the pathogen is drastically reduced. The values ​​are very good», He maintains. Potentially, what the expert is indicating is that if the level of effectiveness of all three variants is verified, much of global society could protect themselves and stop the pandemic. Likewise, if we realize that in addition there are about ten laboratories which carry out their tests in phase 3, the chances of collective success increase.

In any case, it’s worth asking, if they’ve shown efficacy in 90%, 92%, and 94.5% of cases, why haven’t they reached 100%? What happened to this handful of volunteers who fell ill after receiving the active substance and not the placebo? “It is not strange that this does not work in some organizations, because we are not all the same. The medicine may not trigger an adequate immune response in some people. This probably raises the defenses, although they are not sufficient to prevent infections in people who, despite having been immunized, have been infected with covid, ”he warns. “Either way, in those cases who developed the disease, the symptoms may be less severe than those seen if they had not received the vaccine. In Moderna, the 11 severe cases of coronavirus were recorded only in the control group that received the placebo», Complete the explanation.

With 2021 as the horizon getting closer and closer, the competition for the vaccine heats up and, when one of the competitors steps forward, those coming from behind try to do the same, with the spread. even more impactful messages. This has been seen for several months when the world’s largest pharmaceutical companies set out to find the drug that could make a decisive contribution to ending the pandemic. To date, it should be noted that the trials are continuing in phase 3, that is to say that the different variants – based on various technologies of adenovirus, messenger RNA, inactivated virus – are tested in massive experiments with tens of thousands of volunteers. It’s also important to point out that although biotech companies have announced that they will publish preliminary results of this step in prestigious scientific journals, none have done so so far. This is generally important information insofar as only the dissemination of the results makes it possible to verify the rigor of the experiment.

While Moderna does the same with 30,000 candidates undergoing tests in the United States, Gamaleya repeats the success of his “Sputnik V” on 40,000 Russians and Pfizer on 44,000 people from different parts of the planet. In fact, a fraction does it at the military hospital of the city of Buenos Aires, under the command of the doctor specializing in infectious diseases and director of the Children’s Foundation, Fernando Polack.

The curious thing is that, if a dozen companies seek to climb on the podium, the world will need many vaccines which, or can be supplemented by the other tools already known and available (social distance, compulsory use of the chin strap, hand hygiene), and with others (effective treatments) that will surely emerge in the months to come. In Argentina, for example, last week Polack presented a study in which he described that plasma infusion therapy was 60% effective in patients with mild covid if given within 72 hours of first symptom detection. The equine serum, in another order of themes, is being tested and soon there will be news of the trials that Fernando Goldbaum, a reference at the National University of San Martín, coordinates in the health establishments of Buenos Aires. A complex problem requires strategies of the same caliber.

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