Article by Johann Espino
Illustration by Anika Borja
Published 2020 October 02
Vaccines are known to play a significant role in the control and elimination of diseases. They help the body develop immunity by imitating an infection. It allows the immune system to produce antibodies that will be used later on to fight off the actual disease . Usually, it takes a few weeks before the body can effectively develop immunity. If an individual comes into contact with the disease immediately before or after vaccination, their body may not have enough antibodies to fight it off . Vaccines may also require more than one dose in order to effectively develop immunity .
Vaccines usually take years of research and testing before it’s distributed for public use, but in the wake of COVID-19, scientists are racing to produce one by next year. However, vaccines need to undergo a series of tests to prove their safety and effectiveness before they’re approved. These tests can be categorized into five phases: pre-clinical testing, Phase 1 trials, Phase 2 trials, Phase 3 trials, and approval.
Scientists test a new vaccine on cells in the lab. It may also be subjected to animal-testing for immune response. During this testing phase, some of the vaccines being tested can be based on previous treatments or findings that can potentially trigger immune responses against a disease. As of September 30, there are at least 91 preclinical vaccines in active development .
Phase 1 Safety Trials
Scientists give the vaccine to around 20-100 healthy volunteers to determine the safety and dosage of the vaccine. They also test if the vaccine can stimulate the immune system and if it has any serious side effects [2,3].
Phase 2 Expanded Trials
Scientists give the vaccine to several hundred volunteers to determine the most common short-term side effects and to further test its ability to stimulate the immune system. The volunteers may be grouped differently, such as by age, to evaluate the effectiveness of the vaccine [2,3].
Phase 3 Efficacy Trials
Scientists provide the vaccine to thousands of people, some given the actual vaccine while others are given a placebo. This phase proves whether the vaccine can successfully protect against the coronavirus. The safety and effectiveness of the vaccine are tested again to determine other side effects that may not have been observed in the previous phases. According to the US FDA, a COVID-19 vaccine would be able to prevent disease or decrease its severity in at least 50% of people vaccinated [2,3,4].
When countries rush the development of a vaccine, there can be serious consequences regarding its safety and effectiveness. This can be seen in the case of China and Russia wherein they already began distributing vaccines without confirming the results from the Phase 3 trials [3,5].
Regulators in a country review the results of the trials and decide whether a vaccine can be given authorization for public use. During a pandemic, however, emergency use authorization can be given. After the vaccine is licensed, scientists continue to monitor its safety and effectiveness on the population .
Although vaccines usually take longer to be developed, the process can be accelerated in one way which is through combining phases of the testing. An example would be to combine Phase 1 trials with Phase 2 trials .
The vaccine is a vital piece of technology in addressing this pandemic, but it should be recognized that a public health crisis is an interdisciplinary issue. Other factors need to be considered aside from the use of vaccines. There are many ways to tackle a public health crisis ranging from the prevention of infections through social distancing to mass testing and the implementation of a contact tracing system to control the spread of the coronavirus. Addressing this pandemic will take a complex approach that includes, but is not exclusive, to the use of vaccines.
- CDC/NCIRD. Understanding How Vaccines Work [Internet]. 2018. Available from: https://www.cdc.gov/vaccines/hcp/conversations/downloads/vacsafe-understand-color-office.pdf
- CDC. The Journey of Your Child’s Vaccine (Infographic) [Internet]. Centers for Disease Control and Prevention. 2018 [cited 2020 Sep 24]. Available from: https://www.cdc.gov/vaccines/parents/infographics/journey-of-child-vaccine.html?CDC_AA_refVal=https%3A%2F%2Fwww.cdc.gov%2Fvaccines%2Fparents%2Finfographics%2Fjourney-of-child-vaccine-text.html
- Coronavirus Vaccine Tracker. The New York Times [Internet]. 2020 Jun 10 [cited 2020 Sep 24]; Available from: https://www.nytimes.com/interactive/2020/science/coronavirus-vaccine-tracker.html
- Center for Drug Evaluation and Research. Coronavirus (COVID-19) Update: FDA Takes Action to Help Facilitate Timely Development of Safe, Effective COVID-19 Vaccines [Internet]. U.S. Food and Drug Administration. 2020 [cited 2020 Sep 24]. Available from: https://www.fda.gov/news-events/press-announcements/coronavirus-covid-19-update-fda-takes-action-help-facilitate-timely-development-safe-effective-covid
- Dou E. China and Russia are ahead in the global coronavirus vaccine race, bending long-standing rules as they go [Internet]. Washington Post. The Washington Post; 2020 [cited 2020 Sep 24]. Available from: https://www.washingtonpost.com/world/asia_pacific/china-and-russia-are-ahead-in-the-global-coronavirus-vaccine-race-bending-long-standing-rules-as-they-go/2020/09/18/9bfd4438-e2d4-11ea-82d8-5e55d47e90ca_story.html