As of May 2021, the Food and Drug Administration has authorized the use of three vaccine types for the COVID-19 Virus, these include Pfizer-BioNTech, Moderna, and Johnson and Johnson. There exist two other types of vaccines that were developed in the past year, but have not yet been approved for use in the United States; these types include the Oxford-AstraZeneca and Novavax vaccine, which were developed in the United Kingdom. Pfizer and Modern vaccines are messenger RNA (mRNA) vaccines, which use a relatively new
technology. Unlike vaccines that put a weakened or inactivated disease germ into the body, the mRNA vaccines deliver a tiny piece of genetic code from the SARS CoV-2 virus to host cells in the body, essentially giving those cells instructions, or blueprints, for making copies of spike proteins, the red spikes pictured in renderings of the virus.
The Pfizer-BioNTech vaccine was the first approved dosage in the United States, approved on December 11th, 2020. This vaccine was shown to be 95% effective at preventing symptomatic disease. The logistical difficulty with this brand is that it has required shipping in ultra-cold temperature-controlled units, making it rather fragile and more complex to transport. However, in clinical trials, the vaccine was 100% effective at preventing severe disease alongside its 90% efficacy rate upon full immunization. Similar to the Moderna vaccine which we will discuss next, the Pfizer vaccine requires two doses.
Following the approval of the Pfizer-BioNTech vaccine was the Moderna Vaccine, which was approved on December 18th, 2020. Unlike the Pfizer vaccine, the Moderna vaccine can be shipped and kept in long-term storage in standard freezer temperatures, and stored for up to 30 days using normal refrigeration, making it easier to distribute and store over long distances. However, the Moderna vaccine was slightly less effective in clinical trials, yielding about 86% effectiveness in people who are 65 and older, but has 90% effectiveness after full immunization.
Finally, the Johnson and Johnson vaccine was granted approval on February 27th, 2021, and works as a carrier vaccine. Scientists engineer a harmless adenovirus (a common virus that, when not inactivated, can cause colds, bronchitis, and other illnesses) as a shell to carry genetic code on the spike proteins to the cells, which then helps train the body to develop immunity. The Johnson and Johnson vaccine rollout was temporarily halted due to rare side-effects, however, since April 23rd the rollout has been resumed. In comparison to the other two vaccine types, Johnson and Johnson’s vaccine is easier to store and only requires a single dose, making it easier to distribute and administer with an overall 72% efficacy rate alongside a 85% effectiveness rate in preventing severe disease after immunization.