Coronavirus disease (COVID-19): Vaccine research and development

28 October 2020 | Q&A


WHO and its partners are committed to accelerating the development of a COVID-19 vaccine while maintaining the highest standards on safety.

In the past, vaccines have been developed through a series of steps that can take many years. Now, given the urgent need for a COVID-19 vaccine, unprecedented financial investments and scientific collaborations are changing how vaccines are developed. This means that some of the steps in the research and development process are happening in parallel, while still maintaining strict clinical and safety standards. For example, some clinical trials are evaluating multiple vaccines at the same time. However, this does not make the studies any less rigorous.

More information about COVID-19 vaccine development is available here.


WHO is one of the leaders (with Gavi and CEPI) 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 investing in vaccine research and development, COVAX is helping 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.

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.

In addition, WHO is setting up “Solidarity” clinical trials that will efficiently evaluate potential COVID-19 vaccines at sites across the globe.

More information about WHO’s work on COVID-19 vaccine research and development is available here.



In a regular vaccine study, one group of volunteers at risk for a disease is given an experimental vaccine, and another group is not; researchers monitor both groups over time and compare outcomes to see if the vaccine is safe and effective.

In a human challenge vaccine study, healthy volunteers are given an experimental vaccine, and then deliberately exposed to the organism causing the disease to see if the vaccine works. Some scientists believe that this approach could accelerate COVID-19 vaccine development, in part because it would require far fewer volunteers than a typical study.

However, there are important ethical considerations that must be addressed – particularly for a new disease like COVID-19, which we do not yet fully understand and are still learning how to treat; it may be difficult for the medical community and potential volunteers to properly estimate the potential risks of participating in a COVID-19 human challenge study. For more information, see this WHO publication on the ethics of COVID-19 human challenge studies

Small (phase I) safety studies of COVID-19 vaccines should enroll healthy adult volunteers. Larger (phase II and III) studies should include volunteers that reflect the populations for whom the vaccines are intended. This means enrolling people from diverse geographic areas, racial and ethnic backgrounds, genders, and ages, as well as those with underlying health conditions that put them at higher risk for COVID-19. Including these groups in clinical trials is the only way to make sure that a vaccine will be safe and effective for everyone who needs it. 

Opportunities to volunteer for a COVID-19 vaccine trial vary from country to country. If you are interested in volunteering, check with local health officials or research institutions.