Vaccines are the most effective public health tool in combating infectious diseases. The purpose of a vaccine is to induce an effective immune response by exposing an individual to the antibodies of a pathogen, so if and when that person comes into contact with that pathogen in the future, the body is already programmed to immediately respond. Immunization has led to the elimination and control of various infectious diseases.
For widespread public consumption, vaccines must be declared safe, should be inexpensive, and easy to administer. Before introducing a new vaccine into the public, clinical trials are required. Clinical trials are research studies designed to answer specific questions about the safety and/or effectiveness of drugs, vaccines, other therapies, or new ways of using existing treatments. The clinical development of vaccines is conducted in a three-phase process. Phase I is designed to test the safety and immunogenicity of the vaccine. Phase II is designed to assess vaccine preparation, optimal dose, and schedule based upon multiple human variables. Phase III is designed to test efficacy and safety for market approval. On average, a clinical trial can last for several months to several years.
On January 31, 2020, a public health emergency was declared by Health and Human Services (HHS) Secretary in response to the 2019 coronavirus (Covid-19) outbreak. Covid-19 is caused by the coronavirus known as SARS-CoV-2. In response to the public health emergency, several vaccines are being developed and tested in clinical trials at a remarkable rate.
With the development of any new vaccine, the Food and Drug Administration (FDA) is required to ensure the safety, effectiveness, and quality of such vaccine for public usage. However, according to §564 of the Federal Food, Drug, and Cosmetic Act, the FDA Commissioner may allow unapproved medical products or unapproved uses of approved medical products to be used in public health emergencies when no FDA-approved alternative is available. The request for such usage is called an Emergency Use Authorization (EUA). An EUA can be issued to permit the use, based on scientific data, of certain medical products that may be effective in diagnosing, treating, or preventing disease during a public health emergency, thus justifying the medical products’ emergency use before formal approval by the FDA [1].
On December 10, 2020, an FDA advisory panel recommended the approval of the first Covid-19 vaccine for emergency use in the United States. The vaccine was developed between Pfizer and the German biotech company BioNTech. On December 11, 2020, the FDA granted an EUA for the Pfizer-BioNTech vaccine.
The vaccine was issued an EUA for the prevention of Covid-19 for individuals 16 years of age or older after reviewing the safety and efficacy of an ongoing clinical trial that began seven months ago. In a press release, the FDA states “the totality of the available data provided clear evidence that the Pfizer-BioNTech Covid-19 vaccine may be effective in preventing Covid-19. The data also supports that the known and potential benefits outweigh the known and potential risks supporting the vaccine’s use in millions of people 16 years of age and older, including healthy adults [2].” The FDA also notes “[a]t this time, data are not available to decide about how long the vaccine will provide protection, nor is there evidence that the vaccine prevents transmission of SARS-CoV-2 [3].” Pfizer reports their vaccine, after a two-dose regimen, has a 95% efficacy rate meaning the vaccine is 95% effective in preventing disease.
During the beginning of their clinical trials, Pfizer began manufacturing doses of the vaccine for public use contingent on the issuance of an EUA. On December 13, 2020, the Centers for Disease Control (CDC) advisory committee voted and gave their recommendation for approval. With the final approval by the CDC, Pfizer has already begun shipment of available doses to every state and they are prepared to deliver additional doses by the end of this year. Each state then has the authority to determine how the vaccines will be disbursed; although, the CDC recommends priority should be given to health care workers and nursing home residents.
On December 17, 2020, a second major Covid-19 vaccine, developed by Moderna and the National Institutes of Health (NIH), was recommended by the FDA advisory panel for emergency use in the United States. The FDA is expected to approve the Moderna vaccine for an EUA by the end of the day, with doses becoming available as early as next week. The Moderna vaccine is reported to protect against both preventing disease and infection, thus diminishing the possibility of increased community spread of the virus. Results similar to the Pfizer-BioNTech vaccine show that after a two-dose regimen the Moderna vaccine is 94.5% effective in preventing Covid-19 disease with an even higher efficacy rate of preventing severe disease.
[1] Food and Drug Administration. Emergency Use Authorization. 18 Dec. 2020: https://www.fda.gov/emergency-preparedness-and-response/mcm-legal-regulatory-and-policy-framework/emergency-use-authorization
[2] Food and Drug Administration. “FDA Takes Key Action in Fight Against COVID-19 By Issuing Emergency Use Authorization for First COVID-19 Vaccine” FDA Press release, 11 Dec. 2020. FDA Takes Key Action in Fight Against COVID-19 By Issuing Emergency Use Authorization for First COVID-19 Vaccine | FDA Accessed 18 December 2020.
[3] Ibid.
[4] United States. Centers for Disease Control & Prevention. Manual for the Surveillance of Vaccine-Preventable Diseases. Atlanta: Centers for Disease Control & Prevention, 2012.
