March 1, 2021
Americans gained a third weapon against COVID-19 this weekend with the availability of a third vaccine. On February 27, 2021, the U.S. Food and Drug Administration granted Emergency Use Authorization to the new vaccine from Janssen Pharmaceutical Companies of Johnson & Johnson to prevent COVID-19 in adults age 18 and older.
The three vaccines uses the spike protein found on the surface of the SARS-CoV-2 virus to stimulate the immune system. The spike protein is like a key that unlocks a portal called the ACE2 receptor on the surface of human cells and allows genetic material from the virus to penetrate the cell. The Pfizer and Moderna vaccines use the blueprint within messenger RNA (mRNA) to instruct cells to manufacture spike protein. Once the cells are taught by mRNA to produce spike protein, the cells of inoculated people produce enough of it for the immune system to remember and recognize it as an invader and neutralize the virus, preventing the person from becoming ill.
The Johnson and Johnson/Janssen vaccine and one in development by AstraZeneca use a different approach to achieve the same ends. Their vaccines fuse the genetic instructions for producing spike protein to a harmless adenovirus that can invade cells but doesn’t cause disease in humans. Like a long-haul trucker dropping off his cargo, the adenovirus drops off these genetic instructions which teach cells to make spike protein. As with the mRNA vaccines, the spike protein inspires the immune system to memorize how to destroy the SARS-CoV-2 virus on sight.
The third new vaccine platform that Novavax, and Sanofi with GSK are developing works by directly injecting synthetic spike protein.
Watch this video series by LRA President and CEO Kenneth Farber to learn more about all three types of vaccines in development for COVID-19. Also check out this article in which the LRA summarizes the COVID-19 Vaccine Clinical Guidance issued by the American College of Rheumatology to help healthcare providers make decisions about vaccination with their patients. Released February 8, 2021, the Guidance covered the Pfizer and Moderna vaccines since those were the two granted Emergency Use Authorization at that time, but it is a living document evolving as new data is available. If you have questions, most will be answered in our COVID-19 Vaccine Q&A, which includes the latest updates.