Three Candidate Coronavirus Vaccines More Than 90% Effective: What Does It Mean

Florence Cunzolo

11/16/2020 2:37 PM

• Clarín.com

• Good Life

Updated 11/16/2020 2:44 PM

Another week begins with an announcement of the preliminary efficacy of an experimental vaccine against Covid-19.

In this case, Moderna's, which yielded

.

The series had been started last Monday by the communication of Pfizer-BioNTech, with also preliminary results higher than 90%, and the next day the Gamaleya Institute joined with 92% of Sputnik V. Specialists consulted by

highlight that it is of encouraging results, they explain whether the small margin of difference found between the percentages is significant and why the population should continue with the care measures.

"This first interim analysis was based on

, of which 90 cases of Covid-19 were observed in the placebo group versus 5 cases observed in the mRNA-1273 group, resulting in a point estimate of the efficacy of the 94.5% vaccine, "announced the statement issued this morning by the biotechnology company Moderna, from the United States, on the preliminary results of the phase III COVE study, which the company carries out together with the National Institute of Allergies and Infectious Diseases (NIAID) of that country in

.

Phase 3 studies are conducted on tens of thousands of volunteers and what they seek to test is whether the candidates, who demonstrated safety and immunogenicity (ability to elicit an immune response) in previous phases, are effective in protecting against infection.

To do this, the participants are randomly divided into two groups: some are given the experimental vaccine and others a placebo (which does not produce pharmacological effects).

Because they are

studies

, neither the researchers nor the volunteers know what was applied to them.

Interim analyzes are conducted by

(external and independent researchers) that make different cuts.

The American Pfizer and the German BioNTech announced their preliminary results with the first 94 confirmed cases of coronavirus among their volunteers, the Gamaleya Institute of Russia with 20 and Moderna with 95.

in the three trials occurred in people who had not been vaccinated, that is, who had been given a placebo.

"Undoubtedly, the efficacy analyzes that the interim analyzes of the Pfizer, Gamaleya and Moderna vaccines are showing are very encouraging results, with efficiencies greater than 90%; but it must be remembered that for the moment they are

. And they speak of efficacy, which is what measures the percentage reduction in the frequency of an infection among vaccinated versus unvaccinated people. That is, the disease incidence rates are compared between those who received the vaccine and those who received the placebo. That is the efficacy.

and is applied on a large scale. And it is the results of those benefits that a vaccine provides, which previously must have been effective " , explains to

Florencia Cahn, president of the Argentine Society of Vaccination and Epidemiology (SAVE) and one of the main investigators of the clinical trial of the candidate of the c

hina Sinopharm in the country, led by Fundación Hupedes y Vacunar.

From the United States, the Argentine molecular biologist, immunologist and biotechnologist Ernesto Resnik, valued the

of the first interim analysis of Moderna's vaccine and expressed optimism regarding the panorama of vaccines against covid in general, regardless of the platform they use.

"Moderna's has data with people over 65 years of age. Among those infected, it has blacks, Latinos, women, men.

. And they are not so preliminary because it is calculated that with 100 to 150, it is enough The data is sure. It is not the same for the Russian vaccine, which only had 20, the data is still somewhat obscure or mixed, it can change a lot. But, essentially the fact that there are already three vaccines that give these data so good and so I think it is simply a testament to the fact that, beyond the mode of delivery or distribution (via viral envelope or mRNA), they

. That means that eventually the immune system attacks that protein and nothing else, beyond the modality, "explained Resnik when asked by

.

"My expectations are that all vaccines are going to be good because the essence of the vaccine is the Spike protein," he said.

Different platforms

Sputnik V uses a platform based on human adenoviral vectors, obtained from genetically modified viruses so as not to cause infection and to

(the characteristic peaks seen on the surface of the virus) to the body, which awakens the immune system response.

Both Moderna and NIAID (mRNA-1273), as well as Pfizer-BioNTech (BNT162b2), are vaccines based on messenger RNA (mRNA), which is the latest technology in vaccines and everything indicates that the SARS-CoV- coronavirus 2 will be the first pathogen for which one or more based on this platform are authorized, because so far there are none approved for any other infectious agent.

They use only a part of the genetic code of the virus so that the cells of the organism generate the antibodies that allow to protect against the infection.

"If it

is demonstrated that this technology works, the pandemic can help us push the button

on a new approach to modern vaccinology ,

" says an article published in September in the journal JAMA.

Regarding the differences between the two, Emilio Malchiodi, professor of Immunology at the Faculty of Pharmacy and Biochemistry of the University of Buenos Aires and director of the Institute for the Study of Human Immunity IDEHU (UBA-CONICET), highlights: "The one from Pfizer- BioNTech uses

, only the RBD portion, which is the one that binds to the ACE2 receptor in cells. That is, the portion of antigen they use is much smaller. Moderna's uses all of Spike and antibodies would cover everything. Using a small portion has the advantage that the messenger RNA they are using is a little bit more stable. But Moderna's also modified it to make it more stable, so it's also a good candidate. Obviously, the two are good. "

"Moderna says her vaccine could be

. That is also fantastic news," he added.

It is that one of the biggest complexities of the Pfizer candidate logistically is the need for conservation at -70 degrees.

Phase 3 studies are conducted on tens of thousands of volunteers in different countries.

Photo Ted Warren / AP / File.

More than 90%

The FDA (the US regulatory agency) warned manufacturers months ago that they would want to see proof that vaccines can protect

.

The results of the first interim Phase 3 analyzes far exceed that floor.

"Today's is a very positive announcement, like the two previous ones. Between 90 and 94.5%, with 100 cases analyzed, there is no difference. It is the same. It cannot be said that Moderna's is better because it gave 94, 5% ", says Malchiodi, member of the Argentine Society of Immunology (SAI).

Resnik contributes along the same lines: "With such low numbers, with just 100 cases, if you have 5 more or 5 less, it changes from 88 to 95% effectiveness. Okay. This is how it is calculated. For me, 90% already it is spectacular, 92% and 94.5% is also spectacular.

. Above 90% is the hope that with vaccines we will end that nightmare. "

However, the efficacy data obtained in these preliminary analyzes

in the final evaluation and, if authorized, when used in the general population, outside of clinical trials.

What the real effectiveness of the vaccines will be if they are approved is something that cannot be known in advance, as well as

they provide will last.

Maintain the cares

For his part, Cahn emphasizes that positive preliminary data should not relax care in the population.

"The results that we have so far come from interim analyzes, they are efficacy results and, of course, very encouraging, but we still have to continue with all the care measures, because at the moment

" .

And he concluded. " The

thing to keep in mind is that when we have the vaccine, we will not have it at the drugstore or go to a private vaccination center

to aplicárnosla The national state will make the purchase, distribution and will give

to those who are more at risk of having serious forms of the disease, such as the elderly, people with risk factors, health personnel, probably security personnel, but that will have to be determined by the Ministry of Health. That is to say, that still you have to keep waiting and keep taking care of yourself. "

"As much as we all get vaccinated, there

and concerns regarding social distancing, use of chinstraps and washing of hands and surfaces cannot be neglected," Malchiodi warned.

Look also

Sarah Gilbert, the scientist who led the Oxford coronavirus vaccine project: "We must wait for phase 3 results"

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