Hepatitis A and B in persons with learning disabilities living in institutions: the need for vaccination

Hepatitis A and considerations regarding the cost-effectiveness of vaccination programs

Hepatitis A vaccines have demonstrated a high degree of immunogenicity and an excellent safety profile. Immunization of certain populations and patient subgroups is recommended according to specific epidemiological and clinical factors, such as a greater likelihood of acquisition of infection or concerns regarding the risk of development of fulminant hepatitis and death. Therefore, the economic implications of routine and/or targeted vaccination programs in the general population and high-risk individuals have been examined. In this manuscript, the available data from the literature regarding the cost-effectiveness of hepatitis vaccination programs in healthy individuals and in those with chronic liver disease are reviewed.

[Epidemiologic characteristics and prevention of viral nosocomial infections]

OBJECTIVES

To describe epidemiological features of viral nosocomial infections (VNI) and their prevention principles.

EPIDEMIOLOGY

Many factors lead to underestimate VNI: difficulty to distinguish between community-acquired and nosocomial infections for seasonal viral diseases, incubation time leading to symptoms after patient discharge, difficulty for diagnosis. Population at high risks of VNI are the children, the elderly and the immunocompromized patients. The risk of severe diseases is high in this last population. The main reservoir of virus is infected symptomatic or asymptomatic individuals. Asymptomatic carriers, especially health care workers, are a major source of transmission. Main routes of transmission are the fecal-oral route, the respiratory route, cutaneous or mucous contact and blood and body fluids exposure. A review of the main virus involved in VNI is presented.

PREVENTION

Preventive measures, such as strict adherence to standard precautions and, in some instances, to isolation procedures, are critical to control VNI. In a major outbreak situation, it may be necessary to consider cohort isolation. Specific control measures rely on immunization, antiviral drug prophylaxis (varicella-zooster, herpes, influenza, exposure to blood) and clinical and biological screening of organ, blood, tissue and cell donors.

Vaccination contre l'hépatite A chez l'enfant

Hepatitis A is usually considered as a mild disease and is asymptomatic in more than 80% of children less than 5 years of age. Furthermore, incidence of the disease decreased dramatically in France during the past decades. For these reasons mass routine vaccination is not required in our country. However, infected children shed the virus in the community and are responsible for secondary cases, sometimes severe. That is why, despite the cost and the absence of reimbursement of the vaccine, immunisation against hepatitis A is recommended in children attending health-care institutions, in children with chronic liver disease and in those travelling in endemic areas. Prophylaxis around an index case is the main problem because non-specific immunoglobulins, although recommended, are not available in France for this indication. Vaccination in the few days following exposition has been reported to be efficient in household contacts and small communities, including nurseries. This strategy is recommended by the British Advisory Board within the 7 days following exposition, but not in France. However, it can be proposed to the family by paediatricians.

Risk groups for hepatitis A virus infection

We report the conduct and results of a systematic search for evidence of risk of infection with hepatitis A virus (HAV) among blood transfusion recipients, travellers, the military, healthcare workers, sewage workers, foodhandlers, day care assistants, institutionalised subjects, blood transfusion recipients, drug addicts, homosexuals, prisoners and other risk groups such a liver transplantees. We report our recommendations for the use of the HAV vaccine in these groups.