Susceptibility to Hepatitis A in patients with chronic liver disease due to Hepatitis C virus infection: missed opportunities for vaccination

A new study examining whether patients with chronic Hepatitis C virus (HCV) were routinely vaccinated against Hepatitis A virus (HAV) found that vaccination rates were low, even though HAV vaccination is recommended for patients with chronic liver disease.

The results of this study appear in the September 2005 issue of Hepatology, the official journal of the American Association for the Study of Liver Diseases (AASLD). Published by John Wiley & Sons, Inc., Hepatology is available online via Wiley InterScience.

The HAV vaccine has been available since 1995, yet HAV infection continues to be one of the most preventable illnesses in the United States. It can cause severe liver disease, liver failure, and even death in patients who already have chronic liver disease. HAV vaccination was recommended for these patients by the 1996 Advisory Committee on Immunization Practices and numerous other health agencies, but it is not known to what extent it is being carried out.

Researchers led by Edmund J. Bini, M.D., M.P.H of the New York University School of Medicine identified 1,193 patients from January to December 2000 at the Veterans Affairs New York Harbor Healthcare System in New York who had chronic HCV infection. Follow-up information was collected through June 30, 2002 to determine the number of patients who were tested for HAV and the number who actually received the HAV vaccine. Patients were considered to be vaccinated if they received at least one dose of the vaccine. The study also examined the number of vaccine doses received, the proportion of patients who were susceptible to HAV among those tested (indicated by a negative HAV antibody result), the incidence of HAV infection during follow-up and the number of visits patients made to their primary care provider.

The results showed that 53.6 percent of the 1,193 patients had antibody testing performed, and almost half of these were susceptible to HAV infection. Yet only 94 patients received the HAV vaccine and of these, 45 received only 1 dose. Among the 94 patients who received the vaccine, 88 had been tested for HAV antibody. A total of 3 patients with HCV infection developed acute HAV infection, one of whom died of liver failure. All of them were known to be susceptible to HAV, but none had received the vaccine.

"The low rates of HAV testing and vaccination are striking given the presence of recommendations to vaccinate these individuals against HAV since 1996, the long duration of follow-up, and the high number of visits with their primary care provider," the authors state. "These findings have substantial public health implications and represent missed opportunities for prevention."

The authors speculate that the reasons for the low vaccination rates could include patient refusal (such as a belief that patients weren't at risk for HAV infection, doubts about the vaccine's effectiveness, or misconceptions about side effects), a lack of knowledge on the part of health care providers, a lack of resources, or because of a greater need to address more pressing health issues during medical visits.

The authors conclude: "Public health efforts at raising awareness about HAV vaccination in patients with chronic liver disease should be strongly encouraged. In addition, further studies to evaluate patient and provider barriers to HAV vaccination are needed to prevent future missed opportunities for vaccination."