Immunization safety: A global priority – a major contribution of Canada’s international immunization efforts

Immunization is undoubtedly one of the most effective and safest health interventions. Nevertheless, implementation of immunization programs on a worldwide basis faces many challenges. ‘Immunization safety’ is one such challenge that has arisen for many reasons.

Since the inception of a vaccination against smallpox, it has been recognized that adverse events may follow the administration of vaccines. Such adverse events have been reported to be either local (at the site of injection) or systemic, and may be mild or, rarely, severe. While some of these events are indeed due to the vaccine itself, many other reactions are coincidental medical conditions that arise from other causes. The large number of vaccine doses administered increases the chances of postvaccination coincidental events. This often may lead to undue concerns and allegations that may, in turn, pose a real health threat and expose individuals who refuse immunization to the deleterious effects of a disease that they could have avoided.

In the past, the initial focus after report of an adverse event or a series of events was the quality of the vaccine. Because of the need to assure and improve vaccine quality, the World Health Organization (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 (1). Yet, this is not enough.

It has been reported that in developing countries, a substantial proportion of vaccination injections are not carried out in a way that guarantees sterility because of syringe and needle reuse, and/or improper sterilization (2). Infectious diseases, particularly blood borne pathogens, have been transmitted by the very act of immunization as a result of nonsterile injections. In addition, there are reports of unfortunate program mistakes, such as rare but dramatic instances when insulin was mistakenly administered to several children instead of a vaccine in some developing countries. Individuals involved with immunization programs, especially those involved in dealing with adverse events, may be ill prepared to respond to consequences of the event, the media and the public. Understandably, vaccination is expected to be a safe medical intervention that will not lead to harm. Part of this expectation arises because vaccines are given to healthy children and child-bearing women, the latter particularly in developing countries. This contrasts with therapeutic drugs taken to cure or alleviate disease.

In addition, paradoxically, the success of global immunization programs in decreasing the incidence of long-dreaded scourges such as poliomyelitis, diphtheria and measles, as well as in eradicating smallpox in the late 1970s, may actually lead to increased public concerns about vaccine safety.

It is, therefore, not surprising that immunization safety ranks high on the WHO’s priority list and resulted in the establishment of the Immunization Safety Priority Project. The project’s main goal is to establish a comprehensive system to ensure the safety of all immunizations given in national immunization programs by the year 2003. Overall awareness of the importance of safety is vital to the prevention of adverse events following immunization. If adverse events occur, early detection and a quick response lessen the negative impact on health and on the immunization programs. This, of course, highlights the need for each physician to report detected adverse events to public health authorities.

Countries are the primary focus of the Immunization Safety Priority Project. Beyond the countries involved and the WHO, the partner coalition already includes the United Nations Children’s Fund (UNICEF), the World Bank, the Programme for Appropriate Technologies for Health, the Bill and Melinda Gates Children’s Vaccine Program, vaccine manufacturers, and national and international professional organizations. The project is heavily supported by the Canadian International Development Agency (CIDA), one of the contributing development and/or technical agencies.

Canada, through CIDA, currently represents donor countries on the board of the recently established Global Alliance for Vaccines and Immunization (GAVI). GAVI partners include industrialized and developing countries, UNICEF, the WHO, the World Bank, foundations, the vaccine industry, public health institutions, nongovernment organizations, and the research and development community. The GAVI initiative has placed immunization safety high on its agenda. The recently created global fund for children’s vaccines is one of the new financing mechanisms established to help support the GAVI initiative. The fund will provide support to the poorest countries for the purchase of new and underused vaccines, and associated safe injection equipment (auto-disable syringes to prevent reuse and safety boxes). It will also provide funding to help strengthen routine immunization services. This represents a major opportunity for the poorest countries to improve the safety of injection practices.

The four major objectives of the Immunization Safety Priority Project are as follows:

• To ensure vaccine safety from clinical trials to vaccine distribution to the point of use.

• To strengthen research and development of safer and simpler delivery systems.

• To broaden access to safer and more efficient systems for vaccine delivery and sharps waste management. This is an area of concerted action within the common strategic framework of the newly launched Safe Injection Global Network, whose mission is to achieve the safe and appropriate use of all injections worldwide (3).

• To establish efficient mechanisms that detect serious or potentially serious adverse effects following immunization, and to enable a prompt and effective response to vaccine safety issues.

Examples of recent activities conducted through the priority project include the establishment of a Global Advisory Committee on Vaccine Safety to provide a reliable and independent scientific assessment of vaccine safety issues (4); the development of information and training material and activities on postmarket surveillance, and managing and/or monitoring of adverse events following immunization; and partnership building with the media to help foster proper understanding of the issues (5). Interested physicians who would like answers to safety questions may access the web sites of either the WHO <www.who.int/vaccines> or Health Canada <www.hc-sc.gc.ca/hpb/lcdc/bid/di/>.

The priority project aims to develop a prompt and efficient reactive capability to deal with real and alleged vaccine safety situations. This calls for international collaboration, and proper and rapid information exchange. The project is currently pilot testing the use of the Canadian-based Global Public Health Information Network to monitor real and alleged vaccine safety situations on a worldwide basis. This web-based system is already successfully used as an early outbreak warning system.

Both laboratory-based tools and epidemiological approaches are needed to study vaccine safety-related issues. No matter how safe vaccines are or are supposed to be, public health follow-up is needed, as well as detection, rapid reaction and investigative capability. A stimulating opinion piece by Ward (6) was published in a recent issue of the Bulletin of the World Health Organization. Without question, the author advocated for the use of vaccination as a useful and important intervention, but emphasized the need “for human and financial resources for monitoring and studying vaccine safety to stay in step with the accelerating pace of vaccine development” (6).

The Global Public Health Information Network is only one of the many interesting initiatives and activities that Canada has to offer to the global collaborative process to ensure immunization safety. Canada has often been at the forefront of efforts to ensure and monitor immunization safety, including the following:

• the early detection that mumps meningitis was linked to the use of some strains of the mumps vaccine (7);

• the implementation of an active paediatric hospital monitoring system for specific vaccine-preventable diseases and adverse events following immunization, which includes all paediatric hospitals in Canada (Immunization Monitoring Program, ACTive) (8); and

• the establishment of the Advisory Committee on Causality Assessment, an expert advisory group convened by Health Canada to review (at least twice a year) all reports of serious and unusual adverse events following immunization from both active and passive monitoring systems (9).

The above initiatives are a tribute to the great work of paediatricians, the Canadian Paediatric Society, and their collaboration with federal, provincial and local public health officials, as well as with other national professional organizations. Let us hope that this will continue, and that Canada will pursue and strengthen its already existing capacity and wide range of activities to guarantee immunization safety not only nationally but also globally in support of the Global Priority Project on Immunization Safety.