Immunization is undoubtedly one of the most effective health interventions. Nevertheless, implementation of immunization programmes faces many challenges. One such challenge is immunization safety - monitoring of adverse events following immunization, as well as all other aspects of immunization such as vaccine quality, storage and handling, administration and disposal of sharps (1).

It is accepted that adverse events may follow the administration of vaccines. Such events may be mild or severe, at the site of injection or systemic. It has also been recognized that while some of these events are indeed due to the vaccine, many are coincidental and arise because of other medical conditions. The vast number of doses of vaccines administered creates conditions that are auspicious for the occurrence of post-vaccination events which may lead to undue concerns and allegations.

In the past, the initial focus after an adverse event or a series of events was the quality of the vaccine. Because of the need to assure and improve vaccine quality, WHO and national regulatory authorities worldwide have devoted much energy and resources to working with vaccine manufacturers to enhance their compliance with good manufacturing practices.

The availability of vaccines of good quality, however, is not sufficient. It is known, for example, that up to one-third of vaccination injections are not carried out in a way that guarantees sterility, and infectious diseases have actually been transmitted by immunization. In addition, errors occur and individuals involved in immunization may be badly prepared to deal with adverse events. Vaccination is expected to be a safe medical intervention that will not lead to harm. This expectation arises because vaccines are given to healthy children and pregnant women. This situation is in contrast to therapeutic drugs, which are taken to cure or alleviate disease.

Paradoxically, the very success of global immunization programmes in decreasing the incidence of long-dreaded scourges such as poliomyelitis, diphtheria and measles, as well as in eradicating smallpox in the late 1970s, can actually lead to public complacency. If there is no discernible risk from the infectious disease, why be vaccinated against it?

It is therefore not surprising that immunization safety ranks high on WHO's priority list, resulting in the creation of the Immunization Safety Priority Project (ISPP). Countries are the primary focus of this project, whose main target is to establish by the year 2003 a comprehensive system to ensure the safety of all immunizations given in national immunization programmes. It requires an overall awareness of the importance of safety and need for prevention, early detection, and quick response to adverse events following immunization, to lessen their negative impact on health and on immunization programmes equally (2).

The ISPP partners include UNICEF, the World Bank, Program for Appropriate Technologies for Health (PATH), the Bill and Melinda Gates Children's Vaccine Program, vaccine manufacturers, and professional organizations. Several development or technical agencies such as the Canadian International Development Agency (CIDA), the Japanese International Cooperation Agency (JICA), the U.S. Agency for International Development (USAID), and the Centers for Disease Control and Prevention (CDC) are also key participants. WHO is the coordinating agency which acts as Secretariat.

The objectives of the project are to:

• ensure vaccine safety, throughout clinical trials and distribution to point of use;

• strengthen research and development of safer and simpler delivery systems;

• establish efficient mechanisms that detect potentially serious adverse events following immunization and enable prompt and effective response; and

• broaden access to safer and more efficient systems for vaccine delivery and sharps waste management.

The latter activity is an area of concerted action with the Safe Injection Global Network (SIGN), whose mission is to achieve safe and appropriate use of all injections worldwide.

Recent ISPP activities include the establishment of a Global Advisory Committee on Vaccine Safety to provide a reliable and independent scientific assessment of vaccine safety issues; the development of training materials and activities on post-marketing surveillance and managing/monitoring of adverse events following immunization; partnerships with the media; and a WHO/UNICEF/UNFPA statement on safe injections and use of auto-disposable syringes.

A Steering Committee on Immunization Safety has been set up to provide technical and scientific advice to the ISPP. Meeting for the first time in October 1999, members stressed the importance of delivering safe vaccines of high quality and of focusing on preventive and safety assurance. Also highlighted was the value of prompt management of adverse events following immunization, strengthening national regulatory authorities and of collaboration between regulatory authorities and immunization programme managers. The following recommendations were proposed.

• Strategies must be developed to assure advocacy for vaccine safety and target appropriate levels of government and the health care delivery system.

• The overall concept of "cost of a safely immunized child" should be promoted. Complete budgeting for safe delivery of vaccines, including the disposal of residual waste, should be an integral part of financing strategies.

• Immunization safety should be emphasized as a core function of immunization systems during health care reform.

• The capacity at all levels to assess/manage immunization safety concerns should be enhanced.

• WHO/UNICEF and their Member States should expand access to training as a core element of immunization safety. This should include monitoring adverse events following immunization, risk communication/media training, injection safety, and national regulatory authorities functions. The ability to train should be addressed at an early stage in the development of new technologies or programmes, with emphasis on pre-service training.

• National immunization plans should include policies towards safety and waste management, and these policies should be implemented. Early detection, proper response and timely management of vaccine safety concerns, in particular to correct programmatic errors, should be instigated.

References

1. Scholtz, M., Duclos, P. Immunization safety: a global priority. Editorial. Bulletin of the World Health Organization, 78: 153-154 (2000). http://www.who.int/bulletin/

2. Immunization Safety Priority Project (ISPP). http://www.who.int/vaccines/