Developing a new vaccine is a long and complex process; it can take 10 to 12 years. Every disease has its own characteristics, and developing a vaccine to protect against a specific disease requires a unique approach. 

Most diseases are caused by pathogens - typically viruses, bacteria or parasites - that attack the body’s natural immune system. Vaccines are created to stimulate our natural immunity to these infectious organisms in a controlled way and so provide protection from infection or disease.

The challenge faced by our scientists is to develop vaccines that deliver the appropriate strength of pathogen to trigger our own immunity and provide protection.

While every disease will have its own particular characteristics, our work to develop and introduce a new vaccine typically goes through a number of stages:

Research - identifying and isolating a pathogen associated with a disease

Once a pathogen associated with a particular disease has been recognised, the specific part of the pathogen that encourages the immune response needs to be identified. We often conduct this research with academic institutions, as they have a deep understanding of disease biology.  

Discovery - using the isolated pathogen to develop a possible vaccine

Because every disease has different characteristics, each vaccine will have an individual development path. Depending on the disease in question, pathogens can either be reduced in strength or made completely inactive. This renders them appropriate for use in the vaccine so they can raise an immune response without actually causing the disease. In some cases, a combination of molecules - known as an adjuvant system to enhance the body’s immune response - may be included.

Pre-clinical testing - understanding how the potential vaccine works, and how it is likely to affect the body

Before any testing in humans, a new vaccine will undergo careful investigation in the laboratory. The potential vaccine will be checked to ensure purification has not altered its identity, and that it stimulates the appropriate immune response. The effects of adding any adjuvant system will also be evaluated.

Clinical trials - carrying out tests in humans

Testing in people is conducted in three phases, all governed by internationally agreed principles. In phase one, studies on small groups of volunteers evaluate safety, immune effect and tolerance to different doses.  Phase two involves a larger group and confirms formulations and doses, identifies target populations, and establishes the best vaccination approach. Phase three will evaluate the protection given to several thousand volunteers who are at risk from the disease in question.  Clinical trials can take as long as seven years.

Regulatory approval - submitting data and information to government regulators to gain approval to make a vaccine available for use

All the information and data collected during development and trials of a new vaccine are presented to the regulators. Before authorisation is ever granted, all questions raised by the regulators must be fully answered. It may take as long as two years to secure this official registration for a new vaccine.

Monitoring - evaluating the progress of vaccines after launch

Once a vaccine has been introduced to the market, we continue to monitor its use.  This ensures that we build up an understanding of a vaccine’s safety profile and effectiveness is assessed.