The WHO says: “Ensuring the safety and quality of vaccines is one of WHO’s highest priorities. WHO works closely with national authorities to ensure that global norms and standards are developed and implemented to assess the quality, safety and efficacy of vaccines.
The process to develop COVID vaccines is fast-tracked while maintaining the highest standards: Given the urgent need to stop the pandemic, pauses between steps, often needed to secure funding, have been shortened, or eliminated, and in some cases, steps are being carried out in parallel to accelerate the process, wherever that is safe to do. COVID-19 vaccine developers have issued a joint pledge not to seek government approval for their vaccines until they’ve been proven to be safe and effective.
There are many strict protections in place to help ensure that COVID-19 vaccines are safe. Like all vaccines, COVID-19 vaccines are going through a rigorous, multi-stage testing process, including large (phase III) trials that involve tens of thousands of people. These trials, which include some groups at high risk for COVID-19 (certain groups like pregnant and lactating women were not included in vaccine trials), are specifically designed to identify any common side effects or other safety concerns.
Once a clinical trial shows that a COVID-19 vaccine is safe and effective, a series of independent reviews of the efficacy and safety evidence is required, including regulatory review and approval in the country where the vaccine is manufactured, before WHO considers a vaccine product for EUL or prequalification. EUL or Prequalification verifies to those countries that would want to procure a particular vaccine that there has been an assurance by WHO that the regulatory review process, usually in the country of manufacture, has held up to the highest standards. Part of this process also involves a review of all the safety evidence by the Global Advisory Committee on Vaccine Safety.
An external panel of experts convened by WHO analyzes the results from clinical trials, along with evidence on the disease, age groups affected, risk factors for disease, and other information. The panel recommends whether and how the vaccines should be used. Officials in individual countries decide whether to approve the vaccines for national use and develop policies for how to use the vaccines in their country based on the WHO recommendations.
After a COVID-19 vaccine is introduced, WHO supports work with vaccine manufacturers, health officials in each country, and other partners to monitor for any safety concerns on an ongoing basis.”