Hepatitis B is a potentially serious disease, spread by blood and body fluid contact. From 1990 to 1994 the incidence of hepatitis B in Canada was on average about 10.3 per 100,000 per year, with corresponding mortality, morbidity and the potential for long term complications and chronic carriage. The best time to introduce the vaccine into the routine schedule is before children become sexually active. Targeting high risk groups only is an ineffective strategy, which is why the vaccine is being offered for infants or children.
(a) The decision in France was taken in response to pressure exerted by opponents to the vaccine who allege that immunization with the vaccine is associated with the development of some types of neurologic disease. It was not based on scientific evidence.
The French Minister of Health announced on October 1, 1998 that school based vaccination programs would be temporarily suspended, in part due to pressure from opponents to the vaccine. Allegations have been circulating in France, despite a lack of scientific evidence, linking hepatitis B vaccination and the development of demyelinating diseases such as multiple sclerosis, MS. In contrast, the vaccine is still recommended for routine infant immunization, and for adults in high risk groups. More importantly, vaccination is still recommended and available to adolescents through their family doctor's office. The French minister highlighted that this move was temporary, and it will permit a reassessment of the method of delivery of adolescent immunization in school settings. France embarked on a very large scale hepatitis B immunization effort several years ago, to the point where some 25 million doses have been distributed and over one-third of the population have been vaccinated.
(b) The Laboratory Centre for Disease Control, LCDC, Health Canada and the National Advisory Committee on Immunization, NACI, have continued to review available evidence, including results of postmarked surveillance in Canada, in light of the allegations against hepatitis B vaccine. There is no evidence to suggest any change in the current recommendations for the routine use of hepatitis B vaccine in Canada. There is no credible scientific evidence linking hepatitis B vaccination and MS and chronic fatigue syndrome.
The World Health Organization, WHO, has reaffirmed the safety of hepatitis B vaccine and strongly recommended that all countries already using hepatits B vaccine continue to do so, and that countries not yet using the vaccine begin as soon as possible. Health Canada's role with regard to the hepatitis B vaccine is multifaceted.
The Therapeutic Products Program, TPP, reviews the vaccine through a process of careful assessment of pre-market clinical trials to ensure it meets required standards of safety and efficacy. In addition, each lot of vaccine is individually cleared by TPP before being allowed on the market.
The National Advisory Committee on Immunization, reporting to the Assistant Deputy Minister, Health Protection Branch, issues guidelines and recommendations on the use of the product. NACI indeed has recommended routine use of the vaccine and continues to do so.
The Division of Immunization, Bureau of Infectious Diseases of the Laboratory Centre for Disease Control is responsible for the postmarked surveillance of vaccines in Canada, including the hepatitis B vaccine. It undertakes both passive and active surveillance of vaccine associated adverse events and supports an external expert advisory committee on vaccine safety. There have been no concerns regarding MS identified in Canada, and an investigation into whether the vaccine causes chronic fatigue syndrome found no evidence of an association.
The monitoring of vaccine safety relies on many interrelated activities in addition to case reporting. Not only do the Laboratory Centre for Disease Control, LCDC, Health Canada and the National Advisory Committee on Immunization aggregate and assess all reports received to be able to detect any signals of increased, unusual or previously unrecognised adverse events, but in addition Health Canada funds a national program, through the Canadian Pediatric Society, which actively monitors for serious reactions to vaccinations in children and adolescents at 11 pediatric hospitals. The Division of Immunization has also established a committee of medical and vaccine experts to review all the reported serious cases and to further investigated any concerns and take appropriate action as required.
(c) The World Health Organization, WHO, has issued a press release reaffirming the safety and benefit of hepatitis B vaccination. It concluded, after careful review with the assistance of external experts, that available scientific evidence does not demonstrate a causal association between hepatitis B immunization and central nervous system disease, including MS. The Viral Hepatitis Prevention Board, a World Health Organization collaborating centre for the prevention of viral hepatitis, called a technical consultation at the end of September 1998 to review accumulated data. Participants at that meeting were presented with data, including preliminary and still unpublished recent analytic epidemioligic studies conducted in France, the United Kingdom and the United States. Although they acknowledged that the data available to date was limited, none demonstrated a causal association between hepatitis B vaccination and demyelinating disease. They concluded that no evidence was presented at the meeting to indicate a need to change public health policy with respect to hepatitis B vaccination. Routine immunization programs against hepatitis B are in place in 100 countries around the world.
(d) Reassessment of existing evidence has not been considered for the time being in view of the aforementioned notification from WHO. Its statement is based on the conclusion from the international expert meeting at Geneva, on September 28-30, 1998, at which all available information was reviewed in detail—national public health and regulatory authorities, academia, the hospital sector, the pharmaceutical industry and the World Health Organization; experts in public health, epidemiology, immunology, neurology and pharmacology—in response to the decision of the Minister of Health in France to temporarily suspend the school based immunization program.
(e) There two hepatitis B vaccines available in Canada, both of which are recombinant products. This means that they consist of a non infectious subunit derived from the hepatitis B surface antigen harvested and purified from cultures of a strain of yeast. Therefore, no blood products are used at any stage of the manufacturing process. Before the approval of these two vaccines in 1987 and 1990, human plasma was involved in the manufacturing of hepatitis B vaccine. Those “plasma-derived” vaccines have been discontinued with the availability of recombinant products and are no longer in use.
Question No. 194—