In the United States, four COVID-19 vaccines are currently in the final phase of testing before approval by the U.S. Food and Drug Administration (FDA).
“Scientists develop vaccines to help prevent the spread of certain viruses,” said Lucy Esber, junior biomedical science major. “They have even been able to eradicate smallpox, an infectious disease, through vaccination. Ultimately getting a vaccine does you more good than harm, because it introduces your body to the virus, allowing your body to start forming antibodies. Getting vaccinated can also protect those around you from the risk of that virus.”
A vaccine must undergo a three-stage testing process during clinical development, according to the Centers for Disease Control and Prevention. In the first phase, the experimental vaccine is given to small test groups. In the second phase, it is distributed to groups with specific traits such as certain age groups or states of physical health.
“Vaccine trials not only have to show a tolerable safety profile but also must show those study participants in the vaccine group have fewer cases of the target disease than the control or placebo group,” said Dr. Emily Hollinghurst, adjunct professor of pharmacology. “The outcomes assessed in Phases I and II trials are selecting a dose of the vaccine that not only elicits an immune response that would be adequate to prevent infection but also tolerable short-term side effects and no serious adverse reactions.”
In the third and final phase, thousands of people receive the vaccine to ensure that the vaccine is safe and effective for the general population. If the vaccine is successful in the three phases of testing, the FDA can approve it for manufacturing and distribution. The FDA will continue to monitor the production and distribution of the vaccine to ensure it is effective and safe.
Hollinghurst said vaccines normally take multiple years to go through Phase III to ensure participants have time to become exposed to the infection that the vaccine aims to protect people against. However, because of the seriousness of the COVID-19 pandemic, the FDA has prepared an emergency use authorization process with a shorter testing period of two months that includes at least 3,000 test participants.
“The FDA’s duty is to protect the public and ensure short- and long-term safety and efficacy,” Hollinghurst said. “Even after approval, drug companies are required to continuously monitor safety.”
Two of the vaccines in Phase III of testing are viral-vector vaccines produced by AstraZeneca and Johnson & Johnson. The other two vaccines, produced by Moderna and Pfizer, are messenger RNA (mRNA) vaccines.
COVID-19 viral-vector vaccines use other viruses to carry DNA from SARS-CoV-2 to cells, which leads to an immune response. In contrast, mRNA vaccines carry mRNA strands that direct the body to produce SARS-CoV-2 proteins, which cause an immune response.
Hollinghurst said mRNA vaccines can be manufactured more rapidly and for a lower cost than viral-vector vaccines.
As of now, both AstraZeneca and Johnson & Johnson have paused their trials because of illnesses in participants that must be investigated. Hollinghurst said a pause in the trial happens often during the testing process. Safety review boards will look into the causes of the illnesses and, if the FDA approves the vaccine for continued testing, the process will resume.
“A vaccine aims to provide resistance against forms of illness which could be life-threatening,” said Madison Hsieh, senior nursing major. “As a result, doctors will often recommend their patients to receive vaccines for their own wellbeing. Once given a vaccine, the body is enabled to produce antibodies that fight against various illnesses. If scientists were able to design a vaccine specifically for COVID-19, the health of many individuals could be saved.”
Hollinghurst said she believes that a vaccine may be approved for manufacturing by the FDA near the end of December and that distribution of a COVID-19 vaccine may begin in early 2021.
“A vaccine could help to slow down transmission and reduce morbidity and mortality caused by this ruthless virus,” Hollinghurst said.