Hundreds of companies have been racing to create a vaccine that is able to prevent the transmission of COVID-19, ultimately ending this global pandemic. On November 9th, Pfizer (an NYC-based pharmaceutical company) and BioNTech (a German biotechnology company) announced that their vaccine candidate was over 90% effective at preventing COVID-19, following results from phase III of the clinical trial.
What were the Pfizer Vaccine Phase III trial results?
Among almost 44,000 trial participants, Pfizer/BioNTech reported 94 cases of COVID-19. Pfizer reported that the split of cases between the groups suggested that the vaccine was more than 90% effective at preventing disease. Of note, the FDA has required coronavirus vaccines to be at least 50% effective to be approved for emergency use. While the Pfizer vaccine’s effectiveness rate may be slightly reduced once the trial is completed, scientists predict it will stay far above 50%.
What don’t we know?
The scientific community is still in the dark about many aspects of the vaccine – including how long vaccine-induced protective antibodies will last, the severity of infections the vaccine can protect against, and the vaccine’s efficacy in different populations, such as immunocompromised and elderly people.
What are the scientific principles behind an mRNA-based vaccine?
Messenger RNA (mRNA) is a set of molecular instructions that instruct the body’s cells to produce the coronavirus spike protein, which is how the immune system is able to target the SARS-CoV-2 (COVID-19). The mRNA vaccine is modified to increase mRNA translation in vivo and increase immunogenicity by multivalent display, allowing for increased efficacy of the vaccine. The vaccine is further formulated in lipid nanoparticles for an adjuvant effect to antigen presenting cells after intramuscular injection. This mRNA-based vaccine consists of 2 doses, given 3 weeks apart.
What is the future of this vaccine?
Pfizer/BioNTech are planning on seeking an emergency use authorization from the FDA once half of the trial participants will have been monitored for 2 months, another FDA safety requirement. Many other vaccine candidates are expected to announce results from early trials in the near future as well. While it remains to be seen when a vaccine can be mass-administered to the general public, in the words of Professor Ugur Sahin, BioNTech co-founder: “This is a victory for innovation, science and a global collaborative effort.”