Skip to Content Skip to Search

How we discover new vaccines

Our vaccines R&D is centered on discovering and developing prophylactic and therapeutic vaccines to protect people against infectious diseases, cancers and chronic disorders. 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 use these pathogens - or small inactive parts of them - to stimulate our natural immunity and so provide protection against infection.

The challenge faced by our scientists is to develop vaccines that incorporate the appropriate pathogen or component of the pathogen which will trigger our own immunity and provide protection.

Although every disease, infectious or not, will have its own challenges, our work to develop and introduce a new vaccine typically goes through seven stages:

vaccines research development timeline

Research – identifying and isolating a pathogen associated with a disease


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

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 makes them safe for use in the vaccine. In some cases, components of the pathogens can be purified and combined. The addition of molecules - known as adjuvants -  can then promote the body’s immune response.

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, followed by trials in animals. The potential vaccine will be checked to ensure any 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. Animal trials follow strict guidelines laid down by the regulatory authorities and will only be carried out when questions cannot be answered with another method.

Clinical trials – carrying out tests in humans

Woman standing on a street

Testing in humans is conducted in three phases, all governed by internationally agreed principles (see Clinical trials in humans). In Phase I, studies on small groups of volunteers evaluate safety, immune effect and tolerance to different doses. Phase II involves a larger group and confirms formulations and doses and identifies the need for boosters and the best intervals between each dose. Phase III 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.

female scientist with science lab equipment

Clinical trials

Find out about our clinical trials process, how we work with doctors and volunteers throughout this process, and how to become a research volunteer.

Read more

Regulatory approval – submitting data and information to regulators to gain approval for vaccines

All the information and data collected during development and trials of a new vaccine are presented to the regulators. Before authorization is 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.

Supplying, manufacturing and shipping – delivering vaccine supplies to those who need them


Manufacturing faces many challenges - not least ensuring that supply meets demand - which will often mean the new vaccine needs to be produced in large quantities. Different facilities are required to make each new vaccine, and plans will be prepared to have these ready to start production as soon as regulatory approval is granted.

Monitoring – evaluating the progress of vaccines after launch

Once a vaccine has been introduced to the market, it continues to be monitored. This ensures that the experience gathered from its use is captured, and its ongoing safety and effectiveness is assessed. In many cases, such long-term monitoring will be a condition imposed by the regulatory authorities and can lead to the vaccine demonstrating that it might have wider uses than first appreciated.

There are more than 40 GSK vaccines in use around the world, and every one of them has been through the same rigorous process before making it to market. Our vaccines have saved many lives, and their continued effectiveness is a testament to the many long hours (often years) spent in the lab by our scientists in R&D.