Vaccine Development

Vaccines are essential for preventing the spread of communicable diseases. The mechanism by which they work is through imitating a weakened version of the infectious pathogen, thereby stimulating one’s immune system to produce relevant antibodies. Vaccine development is an intricate and rigorous process. There are 7 phases involved to move from the lab and eventually to the market.

(Note: The following article is based on the process of vaccine development within the United States, however the general purpose and methods of the developmental phases are standardized and will stay consistent with the research protocols in Canada).

Research and Development

By studying the biology of the infectious organisms, researchers in this stage develop a template for the vaccine. Researchers may conduct a series of preliminary experiments to test the effectiveness of the template — testing may occur in animals. Once it has been determined that the template is practical, the research moves forward to the next phase.

Pre-Clinical phase

Prior to testing the vaccine on people, researchers perform further animal testing and laboratory reserach to develop a deeper understanding on how the vaccine works. This phase also reveals any potential safety and effectiveness concerns in humans.

Before moving on to clinical development, the researcher must submit results of relevant laboratory tests, manufacturing technology information, and quality assessment of the vaccine to the FDA (Food and Drug Administration). The FDA will evaluate the quality of the preclinical data and conduct separate assessments of the vaccine for quality and safety appraisal. Under the oversight of the FDA, the research moves forward to the clinical phase of vaccine development.

Phase 1

The purpose of phase 1 is to evaluate the safety of the vaccine in humans. Studies will be conducted on a small group (20–100) of healthy control volunteers. A dose-response relationship is evaluated by observing whether any adverse reactions occur with increasing doses. Researchers may also gather information on the effectiveness of the vaccine in inducing an immune response in people. Given a satisfactory safety evaluation, the research moves forward to the next phase of vaccine development.

Phase 2

A randomized-controlled trial (RCT) is performed on a group (100–1000) of healthy controls. In an RCT, subjects are randomly assigned to either the experimental/intervention group (receiving the vaccine) or the control/comparison group (receiving a placebo/alternative treatment). Various dosages are tested on a diverse population of people with different health status, demographic groups, etc. Additional safety and short-term side effects are observed. Tests are also conducted to evaluate the effectiveness of the vaccine in generating an immune response. Once an optimum dosage has been confirmed, the research moves on to the next phase.

Phase 3

The vaccine is administered to a larger group (1000+) of people to gather information on safety and effectiveness data. Comparisons on disease incidence are made between the experimental group and the control group. Less common side-effects are further evaluated in a larger population.

BLA Submission

The manufacturing aspect of the vaccine is assessed by the FDA regarding facility requirements, potential for large-scale manufacturing, and demonstration of production consistency. Once manufacturing reliability is ensured and preclinical and clinical testing have been successful, the company developing the vaccine must submit a Biologics License Application (BLA) with all relevant safety, effectiveness, manufacturing information to the FDA. FDA approval of the BLA permits the company to distribute and market the vaccine.

Phase 4

Once the vaccine has been distributed to the larger population, FDA will monitor any benefits, risks, and short-term side effects. Most side-effects are short-lived and mild (e.g., soreness at injection site, fatigue, fever). Population- based surveillance is required to identify uncommon side-effects or long-term complications. After many rigorous testing, phase 4 completes the final stage in vaccine development and distribution.

Works Cited

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