The NIH has emphasized equity in vaccine distribution and states that “In response to the coronavirus disease 2019 (COVID‑19) pandemic and the societal disruption it has brought, national governments and the international community have invested billions of dollars and immense amounts of human resources to develop a safe and effective vaccine in an unprecedented time frame. Vaccination against this novel coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS‑CoV‑2), offers the possibility of significantly reducing severe morbidity and mortality and transmission when deployed alongside other public health strategies and improved therapies."60 As of March 10, 2021, 75 different vaccines are in clinical trials on humans, and at least 78 in preclinical trials on animals, according to an interactive coronavirus vaccine tracker published by the New York Times.61 Twenty-one vaccines have reached the final stages of testing. As of March 10, 2021, three vaccines have been granted an EUA by the FDA in the United States.61
The COVID‑19 vaccines that have been developed may be vastly different than traditional vaccines, as several different vaccine technologies were used in the development of current vaccines and vaccine candidates in ongoing clinical trials. Prior to the current pandemic, researchers were developing a vaccine against the coronaviruses that caused the diseases SARS and MERS, so there is some proven knowledge about the structure and function of coronaviruses. This accelerated development during early 2020 using various technology platforms for a COVID‑19 vaccine. In December 2020, the first vaccine to receive EUA in the US was a messenger RNA (mRNA) vaccine developed by Pfizer (Pfizer-BioNTech COVID‑19 vaccine).62 An internal assessment published by the FDA determined the vaccine was extremely effective with no known significant risks, although there is some question about whether the vaccine could trigger an allergic reaction in some people.62 No vaccines have received full approval by the FDA, but three have been authorized for emergency use by FDA under an EUA to prevent Coronavirus Disease 2019 (COVID‑19).63
Currently, three vaccines have received EUA are authorized and are recommended to prevent symptomatic COVID‑19 and severe COVID‑19 symptoms in the USA:
Pfizer-BioNTech COVID‑19 Vaccine, (mRNA)
Moderna COVID‑19 Vaccine, (mRNA)
Johnson & Johnson Janssen COVID‑19 Vaccine (Adenovirus viral vector).
As of April 2021, large-scale (Phase 3 or Phase 4) clinical trials are in progress or awaiting initiation planned for five COVID‑19 vaccines in the United States: AstraZeneca’s COVID‑19 vaccine; Janssen’s COVID‑19 vaccine; Moderna’s COVID‑19 vaccine; Novavax’s COVID‑19 vaccine; and Pfizer’s COVID‑19 vaccine.61 Since vaccine distribution began in the U.S. on Dec. 14, more than 120 million doses have been administered, reaching 36% of the total U.S. population, according to federal data collected by the Centers for Disease Control and Prevention.61 The CDC has released “Interim Public Health Recommendations for Fully Vaccinated People,” which will be updated and expanded based on the level of community spread of SARS‑CoV‑2, the proportion of the population that is fully vaccinated, and the rapidly evolving science on COVID‑19 vaccines.64 These guidelines include the guidance that individuals that have been fully vaccinated may: “visit with other fully vaccinated people indoors without wearing masks or physical distancing; visit with unvaccinated people from a single household who are at low risk for severe COVID‑19 disease indoors without wearing masks or physical distancing; and refrain from quarantine and testing following a known exposure if asymptomatic."64
Below is a chart comparing vaccines developed by Monica Gandhi, MD, MPH, professor of Medicine and Associate Division Chief (Clinical Operations/ Education) of the Division of HIV, Infectious Diseases, and Global Medicine at University of California, San Francisco (UCSF)/ San Francisco General Hospital.65,66
This is a summary of Phase 3 published findings by Monica Gandhi, MD, MPH, professor of Medicine and Associate Division Chief (Clinical Operations/ Education) of the Division of HIV, Infectious Diseases, and Global Medicine at University of California, San Francisco (UCSF)/ San Francisco General Hospital. Abbreviations: Neutralizing Abs - Serum Neutralizing Antibody Titers. Th1 and Th2 – Helper T‑cells.