The Mechanism of Action of the Pfizer-BioNTech Vaccine
The German company BioNTech partnered with Pfizer to develop and test a coronavirus vaccine known as BNT162b2, the generic name tozinameran or the brand name Comirnaty. A clinical trial demonstrated that the vaccine has an efficacy rate of over 90 percent in preventing Covid-19.
The SARS-CoV-2 virus is studded with proteins that it uses to enter human cells. These so-called spike proteins make a tempting target for potential vaccines and treatments.
Like the Moderna vaccine, the Pfizer-BioNTech vaccine is based on the virus’s genetic instructions for building the spike protein.
The vaccine uses messenger RNA, genetic material that our cells read to make proteins. The molecule — called mRNA for short — is fragile and would be chopped to pieces by our natural enzymes if it were injected directly into the body. To protect their vaccine, Pfizer and BioNTech wrap the mRNA in oily bubbles made of lipid nanoparticles.
Because of their fragility, the mRNA molecules will quickly fall apart at room temperature. Pfizer is building special containers with dry ice, thermal sensors and GPS trackers to ensure the vaccines can be transported at –94°F (–70°C) to stay viable.
