Before licensure, vaccines’ safety is thoroughly evaluated in early and late phase clinical trials to ensure safety standards are met. Without achieving optimal safety standards, vaccines cannot be licenced for use. In addition, the WHO pre-qualifies vaccines with the aim of ensuring adherence to quality standards that can compromise safety. Furthermore, as the vaccines get administered to millions of people globally, the WHO regularly reviews the safety profile of these vaccines based on reported information. The regular reviews of available information on vaccines' safety is done using evidence based principles. On completion of such reviews, WHO issues revised position papers on each of the vaccines.
Like the medicines which show side effects to some and not all patients during treatment, so do the vaccines when administered to the targeted persons: a few people may experience adverse events following immunization (AEFI). Most common AEFI are mild such as fever. In some rare cases, AEFI can be severe requiring hospitalisation.
For example, according to the Health Resources and Services Administration (HRSA), from 2006 to 2014 over 2.5 billion doses of covered vaccines were distributed in the U.S from which 2,287 were compensated for vaccine related AEFI. This means for every 1 million doses of vaccine that were distributed, 1 individual was compensated.
An AEFI may occur due to the following: vaccine itself; vaccine-quality defect; error during administration; immunization anxiety or coincidental. More details on different causes of AEFI can be found here.The Global Vaccine Safety Initiative (GVSI) has developed a blueprint document that proposes a strategic plan for strengthening vaccine safety activities globally.
Optimal vaccines’ safety is critical to improve uptake of vaccines as well as building public confidence on these lives saving interventions. Vaccines’ safety is therefore central for any immunisation programme aiming to achieve reduction, elimination or eradication of vaccine preventable diseases as is the case with smallpox.
VACFA is partnering with the Vaccines Safety Network (VSN) to ensure reliable information on vaccines safety is made available to the public through online platforms such as website. In addition, through evidence-based principles, VACFA is conducting research on the safety of vaccines such as whole cell pertussis as well as safety of routine vaccines administered to HIV-infected persons.
The Vaccine Safety Net is a global network of websites, evaluated by the World Health Organization, that provide reliable information on vaccine safety.
Vaccines for Africa Initiative (VACFA)
Institute of Infectious Diseases and Molecular Medicine (IDM)
Wernher & Beit North Wing, Room N2.09A
University of Cape Town
Faculty of Health Sciences
Observatory, 7925, Cape Town, South Africa