What are the Stages of Vaccine Development?

Vaccines protect people against infectious diseases. Thanks to rigorous research and testing, the safety and efficacy of vaccines is improving all the time.

Before they are approved for release, vaccines must go through a long and detailed testing process. The development and testing of vaccines involves large teams of scientists, and progresses through multiple stages.

In this article, we put a spotlight on the various stages of vaccine development, tracking the path to approval from research and proof of concept, through to testing and monitoring.

Vaccine Research and Development

In order to find a new vaccine, it is necessary to develop an understanding of an infection, and the structure of the virus or bacterium which causes it. The virus or bacteria will be killed or disabled before it is used to trigger an immune response in the recipient of the vaccine without making them ill. The key to vaccine development is determining how to do this through the use of various technologies.

The research and development (R&D) phase of vaccine development can take 10 years or longer, and in some cases, cost over $1 billion or more. The manufacturing process alone typically takes around 24 months.

In order to find a new vaccine, it is necessary to develop an understanding of an infection, and the structure of the virus or bacterium which causes it.

Proof of Concept

Before a vaccine is tested on humans in clinical trials, it must progress through the ‘proof of concept’ phase.

This stage often involves testing in small animals such as mice. Researchers will look at the vaccine’s ability to cause an immune response in them, making necessary adjustments to improve its efficacy.

If a vaccine shows enough potential during this phase of testing, it can move forward to clinical trials in humans.

Vaccine Testing Phases

The following four phases make up the key human testing period. A vaccine must progress successfully through these phases before it can be approved:

Phase 1

A small cohort of adults will be involved in this initial stage of human testing. The group will usually number no more than 100 people.

During this phase, one objective is to confirm that the vaccine does not present any major safety risks to humans. The most effective dose of the vaccine will also be calculated during Phase 1.

Phase 2

In Phase 2, a larger group – typically of at least several hundred people – will be involved in clinical testing. Participants are selected from the target population (the demographic which is expected to benefit the most from the vaccine).

During this phase, scientists will assess if the vaccine is working consistently, evaluating the immune response created by the vaccine. Phase 2 is also used to note any potential side effects of the vaccine.

Phase 3

During Phase 3 of clinical testing, the size of the participant group increases again. Not only does Phase 3 involve a much larger scale of human participation, but it also provides deeper insights into the performance of the vaccine.

The safety and efficacy of the vaccine will be assessed. Scientists will use this large-scale trial to determine if a vaccine can provide sufficient protection to prevent diseases, reduce the number of disease cases, or reduce harm to the individual.

Phase 3 may involve a clinical trial with a cohort of 3,000 participants or more, in order to assess a vaccine’s safety before it can be approved and awarded a license. This phase is also another opportunity to identify and report potential side effects.

Phase 4

Phase 4 testing typically takes place after a vaccine has been awarded approval by the Food and Drug Administration (FDA). As with all licensed medicines, it is important to continually check the safety of vaccines.

A Phase 4 study, also known as post-license monitoring, is typically conducted by the vaccine’s manufacturer. Testing will continue to monitor the vaccine, ensuring it is safe and effective. Manufacturers will report suspected side effects and evaluate data. New side effects may be added to the product information leaflet, or in the case of more serious side effects, a warning may be issued for a specific group not to receive the vaccine. Phase 4 testing may also look at a vaccine’s other potential uses.

Approval Process

The approval process normally takes place before the fourth phase described above. Vaccines are approved by regulatory bodies such as the FDA (United States), European Medicines Agency (EMA) (Europe) and World Health Organization (WHO) (global).

In the United States, companies submit a Biological License Application to the FDA, which includes data from development and testing, as well as manufacturing details. The FDA reviews data and assesses if a vaccine is safe and effective, before it may approve or license a vaccine.

Post-Approval Monitoring

Even after they are approved, organisations such as the FDA and EMA will continue monitoring vaccines. In the US, systems that comprise this monitoring process include; the Vaccine Adverse Event Reporting System (VAERS), a national vaccine safety surveillance program; Vaccine Safety Datalink (VSD), which conducts vaccine safety studies; and the Clinical Immunization Safety Assessment (CISA) Project, another vaccine safety resource.

Why Cerba Research?

Cerba Research’s vaccine labs underpin vaccine development, facilitating reliable data with standardized protocols and state-of-the-art technology. Collaborate with a trusted vaccine lab partner and benefit from full program support for your clinical trial, from preclinical to late-stage research.