The coronavirus disease 2019 (COVID-19) pandemic continues to ravage worldwide, infecting over 118.15 million people. Caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the infection has claimed 2.62 million lives globally.
More than a year into the coronavirus pandemic, scientists and health experts have developed safe and effective vaccines, including the BNT162b2 by BioNTech and Pfizer.
In a study published in the journal Drugs, a researcher tackled the approval of Pfizer-BioNTech’s COVID-19 vaccine, which has now been used in many countries.
What is the BNT162b2?
The BNT162b2 vaccine is a lipid nanoparticle-formulated, nucleoside-modified messenger ribonucleic acid (mRNA) vaccine that works to prevent COVID-19 infection.
BNT162b2 encodes the SARS-CoV-2 spike protein, which elicits immune responses against the antigen in those who will receive the vaccine. It is a gene-based vaccine, which carries genetic instructions of the production of an antigen by the cells of the vaccine recipient.
The main antigenic target for most COVID-19 vaccines is the surface spike protein, which the means by which the virus binds and fuses with host cells.
For administration, BNT162b2 is available in a multi-use vial that requires cold storage. The vaccine must be thawed and diluted before use. It can be administered through the intramuscular route in two doses, with an interval of 21 days.
After getting the vaccine, receivers will attain full protection against COVID-19 by seven days.
Currently, the vaccine is recommended for people who are 16 years old and above.
Efficacy
The Pfizer vaccine was found to induce robust antibody responses in healthy adults between 19 and 55 years in a non-randomized, open-label phase I/II trial in Germany. In this trial, the researchers assigned the patients to receive two doses of the vaccine.
The study revealed that geometric mean concentrations of spike protein-binding immunoglobulin G (IgG) were increased at 21 days after the first dose.
Further, people who were vaccinated with the BNT162b2 demonstrated neutralizing responses against all strains of the virus. It elicited a robust expansion of SARS-CoV-2 spike protein-specific CD4+ and CD8+ T cells in most of the vaccinated participants.
In terms of protective efficacy, the Pfizer-BioNTech vaccine was 95 percent effective in preventing COVID-19 in participants with no previous SARS-CoV-2 infection. The results came from phase II/III of human trials.
Currently, the pivotal I/II/III trial, which is being conducted on 12 years old and above, is ongoing, with safety monitoring to continue for two years after administering the vaccine’s second dose.
In Germany, the vaccine is being tested in a phase I/II dose-escalation study. Meanwhile, a phase II trial has started recruiting healthy adults in China.
Vaccine approval
The BNT162b2 vaccine initiated its phase I/II clinical trial in April 2020. By December 2020, the vaccine received a temporary emergency use authorization (EUA) in the United Kingdom on a rolling submission that included phase III data from a multinational clinical trial.
The vaccine received approvals from other countries, including Canada, Bahrain, Mexico, Saudi Arabia, and the United States. On December 19, 2020, Switzerland gave a conditional marketing authorization for active immunization to prevent COVID-19 in people who are 16 years old or more.
The efficacy and efficacy of the vaccine have not yet been established in children. However, studies are being conducted to determine if the vaccine is safe to use in younger people below 16.
The World Health Organization (WHO) listed the Pfizer-BioNTech vaccine for emergency use, being the first COVID-19 vaccine to receive emergency validation.
By February 14, 2021, the vaccine became the first COVID-19 vaccine to be granted Special Approval for Emergency in Japan. Further, recruitment is underway for the vaccine’s phase III trial in people between 18 and 55 years old.
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