How does Pfizer’s vaccine work?

Pfizer-BioNTech’s vaccine is one of the two vaccines using the most advanced mRNA technology, but at the same time requires strict storage conditions.
The Covid-19 vaccine, called BNT162B2, was jointly developed by two companies, Pfizer of the US and BioNTech of Germany. The other two names for this vaccine are Tozinameran or Comirnaty A.

Clinical trials of the Pfizer vaccine showed up to 95-96% effectiveness against invading coronaviruses. According to the New York Times , each batch of Pfizer-BioNTech vaccine with 7.5 million doses is produced in 60 days. The most advanced mRNA technology The Pfizer-BioNTech vaccine uses mRNA technology. This vaccine is recommended by the US Centers for Disease Control and Prevention (CDC) for use in people 12 years of age and older. The SARS-CoV-2 virus carries proteins that allow it to enter human body cells. These proteins – known as spike proteins – are the subject of research in the production of vaccines and drugs to treat Covid-19. Coronavirus. Photo: New York Times. Pfizer-BioNTech’s vaccine is based on the genetic makeup of the SARS-CoV-2 virus to create artificial protein spikes. Vaccines use messenger RNA (mRNA), a type of genetic material that human cells process to make proteins. The messenger RNA molecules are very fragile, so they will be broken down by natural enzymes in the human body if injected directly into the human body. To protect the mRNA in the vaccine, Pfizer-BioNTech wraps the mRNA molecules in an oil bubble made of microscopic fat particles. mRNA molecule. Photo: New York Times. Due to their unstable nature, the mRNA molecules in the vaccine will be degraded at normal temperatures. Therefore, vaccines of Pfizer-BioNTech need to be stored at deep cold temperatures, at least -70 degrees Celsius or less. To keep the vaccine of Pfizer-BioNTech stable, special containers are required, including dry ice, heat sensors and GPS trackers. Inject vaccines into the body After vaccination, the molecular particles in the vaccine will collide and fuse with human body cells, releasing mRNA. Human body cells will read the genetic content contained in the mRNA and from there produce protein spikes. The mRNA molecule from the vaccine is eventually destroyed by human cells forever. Vaccine molecules interact with cells. Photo: New York Times. Some protein spikes will form spikes, which rise to the surface of the cell and protrude outward. Cells that have been affected by the vaccine also break down the protein into small pieces on the surface. The protein spikes protruding from the cell, and the protein molecule on the cell surface, will eventually wake up the human immune system. When cells that have interacted with the vaccine die, their fragments contain many protein spikes and protein fragments. These fragments will be picked up by a type of immune cell called molecular antigen-presenting cells (APCs). APC cells activate helper-T cells. Photo: New York Times. Fragments of protein spikes will stick to the surface of APC cells, until helper-T cells detect these fragments. The helper-T cells then trigger the immune system to produce antibodies against the coronavirus. Antibody production Other immune cells, called B cells, can collide with the coronavirus spike protein on the surface of the cell that has interacted with the vaccine, or the floating protein spike debris. Some B cells can adhere to protein spikes. Helper-T cells activate B cells that help produce antibodies. Photo: New York Times. When B cells are activated by helper-T cells, they begin to produce antibodies that attack the spike protein. Antibodies neutralize corona virus. Photo: New York Times. The antibody produced will attach to the spike protein of the invading corona virus. Antibodies mark the virus for later destruction by the body’s immune system. More importantly, the antibody prevents the viral spike protein from attaching to the healthy cells of the human body. To destroy the virus, APC cells activate another type of immune cell called cytotoxic-T cells. This cell is responsible for finding and destroying cells that have been infected by the virus through the signal of protein spike fragments on the surface. Cytotoxic-T cells destroy infected cells. Photo: New York Times. Remember information about corona virus Pfizer-BioNTech’s vaccine is given in two doses, 21 days apart, to help the immune system work most effectively against the corona virus. But because of the lack of time to study, scientists cannot be sure how long the immunity created by the vaccine will last. Preliminary research shows that within 10 days of receiving the first dose, the vaccine begins to build a strong immune system against the virus. It is likely that, after several months of vaccination, the number of antibodies and cytotoxic-T cells will gradually decrease. But the immune system also contains special cells that store information about the corona virus for years, even decades. Each vial of vaccine contains 5 injection doses of 0.3 ml. Vaccines need to be thawed and diluted with saline. After dilution, the vaccine must be used within 6 hours.