World Health Organization WHO since its inception on 7th April 1948 has been working to ensure that everyone, everywhere is protected and to further international cooperation for improved public health conditions
WHO also helps countries set up rigorous safety systems for vaccines and apply strict international standards to regulate them.
Together with scientists from around the world, WHO experts conduct ongoing monitoring to make sure that vaccines continue to be safe also working with partners to help countries investigate and communicate if potential issues of concern arise.
Any unexpected adverse side effects that are reported to WHO are evaluated by an independent group of experts called the Global Advisory Committee on Vaccine Safety.
Any licensed vaccine by WHO is rigorously tested across multiple phases of trials before it is approved for use, and regularly reassessed once it is introduced. Scientists are also constantly monitoring information from several sources for any sign that a vaccine may cause health risks.
WHO ensures that vaccines go through;
Laboratory Testing: Expert scientists test the safety of a potential vaccine in a laboratory first.
Clinical Trials: Promising vaccines enter clinical trials, where people volunteer to test the vaccines. Clinical trials happen in three phases. By Phase 3, the vaccine’s typically being tested in 1000s of diverse volunteers in multiple countries. Clinical trials rigorously tested for safety and effectiveness.
WHO expert doctors and scientists examine clinical trial data to decide whether to approve a vaccine in a country. Multiple vaccines may be approved in a country. Some vaccines may be approved for specific groups of people first.
After a vaccine is approved, scientists continue to monitor its safety as such any irregularities can be effectively checked
Source: World Health Organization.