Article VACCINE DEVELOPMENT, TESTING & REGULATION: WHAT WE SHOULD KNOW Nik Norliza Nik Hassan School of Health Sciences Health Campus, Universiti Sains Malaysia 16150 Kelantan Vaccination is a simple, safe and effective way of protecting human against harmful diseases, before human come into contact with them. To date, there are vaccines available to protect against at least 20 diseases, such as diphtheria, tetanus, pertussis, influenza and measles. Together, these vaccines save the lives of up to 3 million people every year [1,2]. Vaccination uses human body’s natural defenses to build resistance to specific infections and makes the immune system stronger. However, because vaccines contain only killed or weakened forms of germs like viruses or bacteria, they do not cause the disease or put us at risk of its complications. Vaccination is not just about protecting ourselves, but also those around us. However, seriously ill people are advised against getting certain vaccines - so they depend on the rest of us to get vaccinated and help reduce the spread of disease. Our immune systems are designed to remember. Once exposed to one or more doses of a vaccine, we typically remain protected against a disease for years, decades or even a lifetime. This is what makes vaccines so effective. As more people in a community get vaccinated, fewer people remain vulnerable, and there is less possibility for passing the pathogen on from person to person. Lowering the possibility for a pathogen to circulate in the community protects those who cannot be vaccinated due to other serious health conditions are known as “herd immunity.” However, Herd immunity does not protect against all vaccinepreventable diseases. For example, tetanus that is caught from bacteria in the environment, not from other people [1,2]. During the COVID-19 pandemic, vaccination continues to be critically important. WHO has urged countries to ensure that essential immunization and health services continue, despite the challenges posed by COVID-19. WHO is one of the leaders of a global effort known as COVAX, which is speeding up the search for safe and effective COVID-19 vaccines by pooling resources from many different countries. This includes the COVAX Facility, a global risk-sharing mechanism for pooled procurement and equitable distribution of eventual COVID-19 vaccines. In addition to the investment for vaccine R & D, COVAX also helps in scale up vaccine manufacturing capabilities and commiting to buy vaccine doses if vaccines are shown to be safe and effective, with the goal of distributing 2 billion doses where they’re needed most, worldwide, by the end of 2021. Thus, COVAX is the vaccine pillar of the Access to COVID-19 tools (ACT) accelerator, a global collaboration to accelerate development, production, and equitable access to COVID-19 tests, treatments, and vaccines. A Solidarity clinical trials setup by WHO helps in the evaluation of the potential COVID-19 vaccines at sites across the globe.
In general, the vaccine development is a long, complex process, often lasting 10-15 years and involving a combination of public and private involvement. The current system for developing, testing, and regulating vaccines developed during the 20th century as the groups involved standardized their procedures and regulations. At the end of the 19th century, several vaccines for humans had been developed. They were smallpox, rabies, plague, cholera, and typhoid vaccines. However, no regulation of vaccine production existed. In general, stages of vaccine development and testing involved few steps. a) LABORATORY AND ANIMAL STUDIES Exploratory Stage This stage involves basic laboratory research and often lasts 2-4 years. At this phase, federally funded academic and governmental scientists identify natural or synthetic antigens that might help prevent or treat a disease. These antigens could include virus-like particles, weakened viruses, bacteria, bacterial toxins, or other substances derived from pathogens. Pre-Clinical Stage A stage that give researchers an idea of the cellular responses they might expect in humans. A tissue-culture or cell-culture systems and animal testing involved in the assessing the safety of the candidate vaccine and its immunogenicity, or ability to provoke an immune response. Animal subjects may include mice and monkeys. A safe starting dose and method for administering the vaccine in the next phase of research also will be suggested. The pre-clinical stages often lasts 1-2 years and usually involves researchers in private industry. Before the vaccine is subject to three phases of testing, an approval from the U.S. Food and Drug Administration (FDA) are needed. b) CLINICAL STDIES WITH HUMAN SUBJECTS Phase I Vaccine Trials It involves a small group of subjects, usually between 20-80 subjects. If the vaccine is intended for children, researchers will first test adults, and then gradually step down the age of the test subjects until they reach their target. Phase I trials may be nonblinded (researchers and subjects know whether a vaccine or placebo is used). The goals of the phase are to assess the safety of the candidate vaccine and to determine the type and extent of immune response that the vaccine provokes. Researchers may use the challenge model, attempting to infect participants with the pathogen after the experimental group has been vaccinated. The participants in these studies are carefully monitored and conditions are carefully controlled. The promising results will ensure the next stage of trials. Phase II Vaccine Trials This phase involved larger group of subjects in Phase II testing. Some of the individuals may belong to groups at risk of acquiring the disease. These trials are randomized and well controlled and include a placebo group. The goals of Phase II testing are to study the candidate vaccine’s safety, immunogenicity, proposed doses, schedule of immunizations, and method of delivery.
MyHVP Newsletter | December 2020 | page 5
