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Canada Communicable Disease Report

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Volume: 27S3 • September 2001

Viral Hepatitis and Emerging Bloodborne Pathogens in Canada

Prevention and Control of Viral Hepatitis and Emerging Bloodborne Pathogens in Canada

Shimian Zou, Lianne Vardy, Antonio Giulivi

As with other communicable diseases, prevention and control of viral hepatitis, specifically hepatitis A, B, and C, includes measures for the infected individuals and the pathogen they excrete or carry, interruption of the transmission routes, protection of susceptible individuals, and modification of the social or natural factors that influence these elements. Provinces and territories are responsible for the direct delivery or implementation of such measures, and all jurisdictions have guidance documents governing procedures for investigating identified cases and for other necessary public health responses. HC assists in the formulation of such measures and coordinates activities at the national level.

Prevention and control

In collaboration with the provinces and territories, HC held a consensus conference for hepatitis C in 1998, and recommendations from the conference for prevention and control of hepatitis C were published in 1999(1). In addition, HC has prepared a series of guidelines for prevention and control of bloodborne pathogens in health care and other settings(2-6). Professional groups have also issued guidelines, often with support from HC, for matters relevant to the prevention and management of bloodborne infections. These include guidelines from the Canadian Association for Study of the Liver (CASL) on the management of viral hepatitis(7), guidelines from the Society of Obstetricians and Gynecologists of Canada (SOGC) on the management of hepatitis C in pregnant women(8), and the soon to be published guidelines on management of hepatitis C virus (HCV) and HIV co-infection, a joint effort by CASL and the Canadian Infectious Disease Society(9).

Individual measures

Measures for infected individuals involve identification, isolation if necessary, and appropriate treatment and care, which not only help the recovery of the infected but may also reduce the risk of the pathogen being spread to others. For hepatitis B, jurisdictions across the country have introduced prenatal screening. Once a mother is identified as infected, her baby is given hepatitis B immunoglobulin and hepatitis B vaccine immediately after birth(10). Counseling of infected individuals to prevent further transmission is another component of primary prevention(1).

Targeting the pathogen

Measures targeting the pathogen or the materials that may be contaminated by the pathogen consist of proper handling of contaminated materials and adequate disinfection as well as appropriate hospital infection control practices. These measures are generally part of normal medical and health care procedures. HC, provincial/territorial health authorities, and professional organizations issue guidelines or recommendations from time to time to improve existing practices or initiate new ones whenever necessary(2-6). Two articles in this supplement (Germicide Inactivation of Hepatitis B and C Viruses, by Dr. Sattar et al, and Hospital Infection Control and Bloodborne Infective Agents, by Dr. Diaz-Mitoma et al) discuss some of these measures in more detail.

Interrupting transmission

For interruption of hepatitis A transmission, food and water safety is the most important factor. However, prevention of infection during travel or through sharing of contaminated needles for drug injection is also essential(11). More details can be found in the next article in this supplement, Hepatitis A and its Control. For both hepatitis B and hepatitis C, preventing the initiation of drug injection and establishing harm reduction practices among injection drug users hold the key to effective control of transmission. Furthermore, adequate attention should be paid to sexual and perinatal transmission of hepatitis B and potentially hepatitis C. Details can be found in the articles of this supplement specifically dealing with these diseases.

Nosocomial and occupational transmission of bloodborne pathogens such as hepatitis B and C has been recognized as an important risk to health care workers and patients. Various interventions have been implemented to reduce such risks. Examples include the use of disposable medical instruments, such as needles and syringes, sterilization of non-disposable equipment, routine practices and additional precautions (universal precautions) in the handling of materials potentially contaminated with blood or body fluids, as well as vaccination of health care workers against hepatitis B. HC recently issued a series of guidelines for the prevention and control of nosocomial and occupational transmission of bloodborne pathogens(2-4,6).

Transmission of bloodborne pathogens through blood, blood products, other biological drugs, tissues, and organs is a special type of nosocomial transmission. Although the risk of such transmission has been reduced dramatically thanks to the effective implementation of various measures, including donor selection and blood screening, continuous vigorous safeguarding of these products can never be overemphasized.

Protecting susceptible individuals

Susceptible contacts of infected individuals should be identified through the public health responses (contact tracing), and appropriate measures need to be taken to protect them. Individuals susceptible to hepatitis A(11,12) and hepatitis B(10,13) infection can be protected by passive as well as active immunization. Immunoglobulin preparations specific to hepatitis A or hepatitis B virus are effective against the respective pathogen and can be used immediately after exposure to obtain prompt, though short-term, protection. Safe and effective vaccines are also available for individuals susceptible to these two pathogens, and various programs exist in different jurisdictions across the country. For instance, universal pre-adolescent vaccination against hepatitis B has been implemented across the country, and HC has initiated a study that is being carried out by an expert working group to assess various strategies for hepatitis A vaccination. In the case of hepatitis C, support for education and harm reduction measures and prevention of injection drug use initiation contribute to the prevention of infection.

Public health responses

Investigation and control of outbreaks or unusual clusters of viral hepatitis are an essential part of public health intervention activities. For hepatitis A, in addition to epidemiologic investigation, vaccination of contacts or community members with or without immunoglobulin is recommended(12).

Measures for the prevention and control of emerging bloodborne pathogens mainly focuses on the development of rapid risk assessment capacities. Once a new or re-emerging bloodborne pathogen is identified and its risk assessed, appropriate public health responses can be taken accordingly to prevent and control its spread. Two articles in this supplement, SEN-V and the Rapid Response Surveillance System, and Cytomegalovirus, Herpesvirus 6, 7 and 8, and Parvovirus B19 in Canada, describe preliminary data or work in progress on new or re-emerging bloodborne pathogens; as well, the potential challenges of xenotransplantation are discussed by Dr. Laderoute.

In addition to primary prevention measures, prevention of disease progression and management of infected cases are also important. For example, hepatitis patients are strongly encouraged to eliminate or reduce the consumption of alcohol(7).

At the population level, various health promotion activities, such as public education and awareness, are essential to effective prevention and control of viral hepatitis and emerging bloodborne pathogens. To know how a disease is caused, transmitted, and influenced and how to prevent or control it is necessary but not sufficient. Equally important is the application of this knowledge for the prevention and control of diseases. For example, there is enough knowledge about hepatitis A virus, its transmission, the risk factors associated with transmission, and the means to protect susceptible individuals; there are also effective and safe immunoglobulin preparations and vaccines for hepatitis A infection. Nevertheless, outbreaks occur yearly in communities and among those exposed to contaminated food or water. For hepatitis C and to a lesser degree hepatitis B, sharing of contaminated needles through injection drug use is known to account for the majority of infections. However, how to prevent transmission of hepatitis B, hepatitis C, and other bloodborne infections through injection drug use remains a major challenge, which is a current focus.

Nosocomial and occupational exposure to bloodborne pathogens has been reduced significantly in recent years, but the risk is far from eliminated: education of health care professionals and vigilance on their part are still warranted. More effort is needed in this area to improve the effectiveness of prevention and control activities aimed at viral hepatitis and emerging bloodborne infections. Recently, HC released a supplement issue addressing various aspects of hepatitis C prevention and control(14). This will serve to assist professionals and the public alike in the fight against the virus, which is already the number one reason for liver transplantation in this country.

References

  1. Health Canada. Hepatitis C - prevention and control: a public health consensus. CCDR 1999;25S2:1-23.

  2. Health Canada. An integrated protocol to manage health care workers exposed to bloodborne pathogens. CCDR 1997;23S2:1-16.

  3. Health Canada. Proceedings of the consensus conference on infected health care workers: risk for transmission of bloodborne pathogens. CCDR 1998;24S4:1-28.

  4. Health Canada. Infection control guidelines: hand washing, cleaning, disinfection and sterilization in health care. CCDR 1998;24S8:1-55.

  5. Health Canada. Infection control guidelines: infection prevention and control practices for personal services: tattooing, ear/body piercing, and electrolysis. CCDR 1999;25S3:1-82.

  6. Health Canada. Infection control guidelines: routine practices and additional precautions for preventing the transmission of infection in health care: revision of isolation and precaution techniques. CCDR 1999;25S4:1-142.

  7. Canadian Association for the Study of the Liver. Canadian consensus conference on the management of viral hepatitis. Can J Gastroenterol 2000;14(Suppl B):5B-20B.

  8. Society of Obstetricians and Gynecologists of Canada. Clinical guidelines regarding the reproductive care of women living with hepatitis C infection. Health Canada, 2000.

  9. CASL and Canadian Infectious Disease Society. Management guidelines for the HCV/HIV co-infected adults - recommendations of a multidisplinary expert panel. Health Canada 2000.

  10. National Advisory Committee on Immunization. Hepatitis B vaccine. In: Canadian immunization guide, 5th edition. Ottawa: Health Canada, 1998:90-102 (Minister of Public Works and Government Services Canada, Cat. No. H49-8/1998E.)

  11. National Advisory Committee on Immunization. Hepatitis A vaccine. In: Canadian immunization guide, 5th edition. Ottawa: Health Canada, 1998:83-89 (Minister of Public Works and Government Services Canada, Cat. No. H49-8/1998E.)

  12. National Advisory Committee on Immunization. Supplementary statement on hepatitis A vaccine. CCDR 2000;26(ACS-4):12-8.

  13. National Advisory Committee on Immunization. Statement on alternate adolescent schedule for hepatitis B vaccine. CCDR 2000;26(ACS-5):19.

  14. Hepatitis C Division, Health Canada. Hepatitis C: Canadian perspectives. Can J Public Health. 2000;91(Suppl 1):S1-S44.

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