It is the first to show preliminary phase 3 data. The first results show 90% effectiveness: what it means.
At the end of March, the American pharmaceutical company Pfizer and the German biotech BioNTech announced that they were working on a potential vaccine against Covid-19 based on messenger RNA (mRNA) technology. Just seven months later, it is the first experimental candidate to yield preliminary phase 3 data. Through a press release, it was reported that it showed an efficacy greater than 90%, according to the evaluation of the first data of the more than 43,000 volunteers from different countries (including Argentina) who participate in the study.
Its about first interim efficacy analysis conducted by the Data Monitoring Committee (an external and independent group), which evaluated 94 confirmed Covid-19 cases among trial participants. “The division of cases between vaccinated individuals and those who received the placebo indicates an efficacy rate of the vaccine greater than 90%, 7 days after the second dose. This means that protection is achieved 28 days after the start of the vaccination, which consists of a 2-dose schedule, “the statement states.
In the previous phases, the candidate had demonstrated safety (being well tolerated and not generating serious adverse effects) and immunogenicity, that is, the ability to develop an immune response in the body. Phase 3 seeks to determine if that ability translates into real protection. For this, the participants are randomly divided into two groups (neither the volunteers nor the researchers know which one is assigned to): some are given the experimental BNT162b2 vaccine and others a placebo (an inert substance at the level of pharmacological). The results of the first interim analysis known today show that 90% of confirmed infections occurred in the placebo group.
Consulted by Clarion, Emilio Malchiodi, professor of Immunology at the Faculty of Pharmacy and Biochemistry of the University of Buenos Aires, director of the Institute for the Study of Human Immunity IDEHU (UBA-CONICET) and member of the Argentine Society of Immunology (SAI), considered to the announcement one “great news”, but warns that, for the moment, it is a press release without further details. Both companies said they plan to submit data from the full trial to a peer-reviewed scientific journal.
“The newsletter reports only on 94 volunteers, without details, who were infected and it is assumed that only 8 would be vaccinated and that the others would have received placebo; but they are only inferences that they claim 90% effectiveness. Is a large percentage“said Malchiodi. Can it be sustained?” Impossible to know, but it can be, “he replied.
According to the statement, as the study continues, the final efficacy percentage of the vaccine may vary.
The FDA (the US regulatory agency) made candidate vaccine manufacturers a condition that, for approval, they should demonstrate that they can protect at least 50% of those who receive them. “Others say 60% would be necessary, so Pfizer is excellent then,” Malchiodi insisted. However, he stressed that “eight vaccinated were infected, and if the effectiveness is lower, there will be a higher percentage of infected, so the optimism of the Government and many people needs a ground wire. As much as we all get vaccinated, there will continue to be people getting infected and concerns about the social distancing, use of a chinstrap and hand washing and surfaces may not be neglected, “he stressed.
The phase 3 trial that began on July 27 has enrolled 43,538 participants in the United States, Brazil, Argentina and Germany, of which 38,955 of which have already received the second dose of the vaccine or the placebo, according to the group to which they have been assigned.
The final analysis will be performed when a total of 164 confirmed cases of Covid-19. The study will also evaluate the potential of the candidate vaccine to provide protection against Covid-19 in people who have had previous exposure to SARS-CoV-2, as well as the ability to protect against serious disease. In addition, in September the companies obtained authorization to start testing it in boys and girls from the age of 12, in a study carried out in the United States.
Regarding safety, the monitoring committee nor reported no serious problems so far. Pfizer and BioNTech would request emergency authorization from the FDA (the US regulatory agency) in the third week of November, they advanced. However, participants will continue to be monitored to assess long-term safety and security during two years after receiving the second dose.
The candidate was developed using a genetic platform called messenger RNA (mRNA), which uses only a part of the genetic code of the virus so that the cells of the body generate the antibodies to protect against infection. It is the latest technology in vaccines, so it is still there are none approved in the world for other infectious agents.
“One issue to note is that although the research and development process was very fast, the production of the amount of vaccine necessary to immunize millions of people is not that fast. Although they will already be producing at risk, the issue is: How many producer plants are there? Of the more established methodologies (inactivated viruses), there are numerous plants because other calendar vaccines are made, so producing a new vaccine is relatively simple: you stop the production of the others and start with the new one. But this technology it is brand new and no massive functioning plants“Malchiodi warned.
Based on current projections, companies expect to produce globally up to 50 million doses of vaccines in 2020 and up to 1.3 billion doses in 2021.
She is one of the candidates that is part of the “vaccine mix” that the Government negotiates at risk (before approval). “Although we had the availability of Pfizer vaccines as of December, they had no magnitude,” said Health Minister Ginés González García last week at a press conference given to the Argentine Network of Scientific Journalism (RADPC). The information on the number of doses that would arrive from that month, is not entirely clear. While the head of the health portfolio estimated one million, President Alberto Fernández spoke of 750,000.
“The other issue with this vaccine is that it is the one that requires the lowest storage temperature. It is not easy to reach the entire population with this vaccine, due to the infrastructure issue,” said the director of IDEHU. Candidate BNT162b2 requires capacity from ultrafríoTherefore, the Government estimates that it will not be an option for the most remote vaccinations.