The effectiveness of vaccines is not the only thing that matters …

As the world continues to fight to stop coronavirus infections, which surpass 130 million people infected, a recent video posted by the Vox news site explains why vaccines, regardless of the brand or the efficacy obtained by each of them, are the only solution to foresee the end of the new coronavirus pandemic.

The video came in response to the mayor of Detroit, United States, who in March, it rejected 6,000 doses of the vaccine developed by the Johnson & Johnson laboratory. “The Moderna and Pfizer vaccines are the best and I will do everything possible to ensure that our citizens have the best,” said Mike Duggan, referring to the level of effectiveness achieved by each of the vaccines.

According to the evidence presented, the Pfizer was 95% effective, Moderna 94% and Johnson & Johnson 66%.

The video uses the mayor’s rejection as the trigger for why these numbers are not important in determining the true effectiveness of vaccines. In this sense, the video highlights that the variation in the efficacy result between one vaccine and another depends on the context (time and place) in which the tests were carried out with the sample of people vaccinated with the drug and the placebo.

The efficacy of the vaccine is calculated with the group is testing thousands of people, half of whom receive the vaccine and the other half receive a placebo then we analyze who and how many of them contracted the disease.

In the first Pfizer-BioNTech trial, 43,000 people were studied, 170 of whom were infected with COVID-19. Of those infected, 162 people had received the placebo and 8 the vaccine, meaning those who received the vaccine were 95% less likely to contract the disease.

Vaccine effectiveness is always calculated the same way, the video explains, but each study was performed under different circumstances. The Moderna and Pfizer studies were both conducted at the same time in the United States, while the Johnson & Johnson studies were conducted a few months later with samples from both the United States and other countries.

Two things happened at that time: between October and January – when Johnson & Johnson did the tests – The United States has seen a spike in infections therefore the chances of contracting the virus increased and new variants of the virus appeared in other countries that have pushed new waves of infections.

In South Africa, for example, most cases in the Johnson & Johnson clinical study were exposed to the new variant, not the original strain studied in the United States.

Dr Amesh Adalja, specialist at the Johns Hopkins University Center for Health Security, said: “If you try to make a comparison between each vaccine, they must have been studied in the same clinical trials, with the same inclusion criteria, in the same parts of the world, at the same time ”.

Beyond this difference, the specialists specified that the efficiency number is not the only important thing because preventing all infections is not always the goal of a vaccine.

For Adalja, “the objective of the vaccination program against covid-19 is not necessarily to reach zero covid-19, but to stop this virus, to suppress its capacity to cause serious infections and hospitalizations”. In this direction All vaccines have been shown to prevent 100% hospitalizations and deaths.