COVID-19 Vaccine Candidate 90% Effective, Says Pfizer

The researchers conducted an interim analysis after 94 participants developed COVID-19 to detect how many received the vaccine

American pharmaceutical Pfizer's COVID-19 mRNA vaccine candidate produced in collaboration with BioNTech has showed 90 per cent protection against COVID-19 in its interim analysis of phase 3 trials, Pfizer said on Monday. By the third week of November, the drug conglomerates plan to apply to the US Food and Drug Administration (FDA) for Emergency Use Authorization.

Over 43,538 participants who have not been infected by SARS-CoV-2 across US, Brazil, Argentina, Germany, South Africa and Turkey are currently participating in the Phase 3 trials that started on July 27. The participants are required to take two doses of the BNT162b2 vaccine. Three weeks after the first dose, over 38,955 participants received the second dose.

Interim analysis are tests conducted to find whether the clinical trial is on track to achieve its hypothesis. The data monitoring committee of the trial had pre-determined to check whether the vaccine was protecting against the virus after 32 patients tested positive for SARS-CoV-2. After much deliberation, the data monitoring committee decided to raise this number to 94 participants.

As the clinical trials are double blind trials where the researchers and the patients do not know whether they are receiving the vaccine or a placebo, the researchers had to analyse whether these 94 had received the vaccine or the placebo. On assessing, the researchers found that seven days after receiving the second dose, more than 90% of the participants who received the vaccine were protected from SARS-CoV-2.

This implies that from the 94 participants who were infected by SARS-CoV-2, only around 10 per cent had received the vaccine while the rest had received the placebo. Pfizer has not revealed the exact number of participants who received the vaccine or the placebo. Barring these 8 or 9 people who received the vaccine and tested positive for COVID-19, all the other participants who received the vaccine did not contract the virus.

As the interim analysis was carried seven days after the second dose, the pharmaceuticals postulate that protection against COVID-19 is achieved 28 days after the initiation of vaccination.

While Pfizer CEO Albert Bourla and German BioNTech CEO Ugur Sahin called it a "great day for science and humanity" and "a victory for innovation, science, and a global collaborative effort" respectively, the vaccine efficacy rates could well undergo changes. As the trials are continuing, another analysis will be conducted once over 164 participants have tested positive for COVID-19. This analysis will present a clearer and more robust view of the longevity of the vaccine against COVID-19 thus highlighting its efficacy.

The results of the study with 164 positive cases are expected by the third week of November post which the companies plan to approach the FDA for Emergency Use Authorization. In emergency use, officially unapproved products are permitted to be used in health emergencies for diagnosis, treatment or prevention due to the lack of adequate, approved, available alternatives.

How Will The mRNA Vaccine Fight COVID-19

Currently, there are no active mRNA vaccines that are being used for human use. In viruses, RNA is the genetic code, a part of which is removed by scientists and coated in lipids for its effective entry into the human body. After injection, the vaccine enters the cell where the RNA is released and tries to form the coronavirus spike protein. In response, the human body elicits an immune response.

The immune system produces antibodies against the RNA and activates memory T cells to destroy infected cells. These antibodies and T-cells remain in the body and are activated once a person is exposed to SARS-CoV-2.

What Is Interim Analysis

The 90 per cent efficacy rate is a preliminary finding through the interim analysis of the ongoing clinical trial. Interim analysis is conducted to gauge whether a particular clinical trial is on track to deliver the findings and results that it is intended to. These interim analyses assist the researchers in tweaking and modifying the study protocols if necessary.

In this trial, the researchers had pre-determined that they would test the efficacy once 94 patients tested positive for coronavirus. Through these findings, the researchers can now add other end points on the safety as well as the efficacy of the vaccine candidate.

Will The Vaccine Be Available For Everyone Immediately?

No, the two pharmaceuticals intend to first fulfil the FDA's criteria for Emergency Use Authorization. The companies are now going to check how many people are protected against the virus 14 days after the second dose was administered. Along with this, the FDA demands data on the safety showing that there are no adverse reactions to the vaccine. Pfizer and BioNtech are accumulating safety data for a median of two months to present to the FDA.

Along with the safety data, the FDA will also require all the manufacturing data of the vaccine. Even after all this data will be provided, the vaccine will only receive emergency use authorization. To understand whether the vaccine has a long-term impact, the participants will be monitored for the next two years.

Even though it still awaits all these procedures, the pharmaceuticals have stated that they will be able to produce over 50 million doses by the end of this year and around 1.3 billion doses in 2021. However, storage of this vaccine is still a potential challenge as it requires to be kept at -80 C. Only countries with the requisite infrastructure can avail of the Pfizer- BioNTech vaccine if other countries also permit it to be used.

The researchers have also stated that they will test the vaccine in people who have earlier been infected by SARS-CoV-2 to test the vaccine's effectiveness.

Updated On: 2020-11-09T20:45:11+05:30
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