{"id":240875,"date":"2021-06-27T12:36:25","date_gmt":"2021-06-27T16:36:25","guid":{"rendered":"https:\/\/oncubanews.com\/en\/?p=240875"},"modified":"2021-06-27T12:36:25","modified_gmt":"2021-06-27T16:36:25","slug":"how-was-the-efficacy-of-the-cuban-covid-19-vaccine-candidates-calculated","status":"publish","type":"post","link":"https:\/\/oncubanews.com\/en\/cuba\/how-was-the-efficacy-of-the-cuban-covid-19-vaccine-candidates-calculated\/","title":{"rendered":"How was the efficacy of the Cuban COVID-19 vaccine candidates calculated?"},"content":{"rendered":"

Just a few days ago, the announcements about the efficacy of <\/span>Cuba\u2019s two main COVID-19 vaccine candidates<\/span><\/a>, the result of the third phase of their clinical trials, made headlines. First, 62% of Soberana 02 was reported in its two-dose scheme \u2014 one of the two administered in the study \u2014, and then that of the three doses of Abdala, at a remarkable 92.28%.<\/span><\/p>\n

Since then there have been many reactions and comments inside and outside the island. Satisfaction, pride, joy and even euphoria have prevailed not only among the experts and authorities of the country, but in the general population and also among people from all parts of the world, who see in these drugs an indisputable success of Cuban science and a hope in the face of a disease that has kept the planet in suspense for more than a year and has already taken millions of lives.<\/span><\/p>\n

However, the incredulity, suspicions, denial and discredit of some have not been lacking either, more for political than scientific reasons, and also those who, from a more measured, more critical stance \u2014 in the broadest sense of the word \u2014, and even without ignoring the result, have called for not shouting from the rooftops until there is more data to help unravel and support the announced figures \u2014 as has happened with other already registered vaccines \u2014, and for their validation by the international scientific community and global entities such as the World Health Organization (WHO).<\/span><\/p>\n

After the emotion because of the news, Cuban specialists provided this Thursday more details on the calculation of the efficacy of both vaccine candidates and addressed the steps to follow after revealing that necessary indicator, both for the massive use of the preparations on the island \u2014 at a time when the country is reporting the highest numbers of daily infections and <\/span>active cases<\/span><\/a> of the entire pandemic \u2014 as well as for its recognition and commercialization beyond its borders.<\/span><\/p>\n

\"Press
Press conference on the efficacy of the Cuban COVID-19 vaccine candidates, with scientists and executives of the state group BioCubaFarma, in Havana, on June 24, 2021. Photo: Otmaro Rodr\u00edguez.<\/figcaption><\/figure>\n

Blessed efficacy<\/b><\/p>\n

The percentage of efficacy is the data that everyone expects from the COVID-19 vaccine, which has taken all the spotlight in the race against the clock to produce immunogens against <\/span>SARS-CoV-2<\/span><\/a> and prevent the development of the symptomatic disease as best as possible. Its calculation, which is derived from conducting phase 3 clinical trials with a significant number of people, is not exactly simple and is like the jewel in the crown of the research carried out, after determining the safety and ability to generate immune response in the previous stages of the study.<\/span><\/p>\n

Thus, the high efficacy reported by the Pfizer-BioNTech, Moderna and Gamaleya (Sputnik V) vaccines, all above 90%, quickly became headlines and mandatory references in the current context. Meanwhile, other internationally recognized and used formulas, such as those of AztraZeneca with the University of Oxford, the single-dose of Johnson & Johnson, the Chinese Sinopharm and the Indian Covaxin stand at more than 70%. Such numbers do not reflect the ability of these preparations to prevent infection, but rather to avoid symptoms of COVID-19 and in many cases decrease \u2014 even when they continue to provide protection \u2014 against new, more contagious strains of the coronavirus.<\/span><\/p>\n

As Dr. Eulogio Pimentel, vice president of the state group BioCubaFarma, <\/span>explained this Thursday<\/span><\/a> on the Mesa Redonda television program, the \u201cvaccine efficacy\u201d is defined by the WHO as the percentage of reduction in the incidence of the disease in the vaccinated subjects with respect to the group given placebo in the studies. This is determined \u201cunder the standards and supervision of good clinical practices required by clinical trials\u201d and is expressed mathematically as \u201cone minus the risk of getting sick when you are vaccinated among the risk of getting sick when you are not vaccinated (VE = 1 \u2014 Relative Risk = 1 \u2014 Risk in the vaccinated person \u00f7 Risk in the unvaccinated person).\u201d<\/span><\/p>\n

According to these calculations, that a vaccine is, for example, 66% effective \u201cdoes not mean that, of every 100 people, 44 will get sick and 66 will not get sick, but that, if they are vaccinated, there is a 66% probability of not getting sick,\u201d clarified the specialist, who pointed out that in the case of \u201cvaccine efficacy,\u201d although it is related to efficacy, it is not measured in a controlled environment like this, but in its open and massive application in society , \u201cwhich means there is no supervision by the product promoter or the trial\u2019s principal researchers.\u201d<\/span><\/p>\n

\u201cThe less people are able to be immunized in a population, the less the efficacy\u201d of a vaccine is seen, said Pimentel, and stressed the importance not only of getting vaccinated but also of completing the immunization scheme for each vaccine, so as not to leave \u201ca gap for the entry and spread of the virus.\u201d<\/span><\/p>\n

Coronavirus: eficacia de f\u00f3rmulas cubanas abre esperanza a primera vacuna latinoamericana<\/a><\/p><\/blockquote>\n