Hepatitis A
Table of Contents
Hepatitis A · Hepatitis
B · Hepatitis
C · Hepatitis
of Unknown Etiology
Hepatitis Main Page
What Is Hepatitis A?
Hepatitis A is a virus that causes acute hepatitis. The symptoms of hepatitis A virus (HAV) infection include nausea, vomiting, poor appetite, fatigue, icterus (yellow eyes), and jaundice. The virus is transmitted by the fecal-oral route and survives very well in the environment, including in water, food, and on the hands of infected persons who do not wash with soap after they go to the bathroom. HAV infection is rarely fatal and does not cause chronic hepatitis, but infected persons, especially older children and adults, can get very ill and miss work and school. An effective vaccine is now licensed for the prevention of HAV infection.
HAV infection has been a major disease problem for Alaska Natives. The disease typically occurs and recurs in a cyclic pattern. The latest statewide epidemic began in late 1986 and ended in 1994. Over 2,500 icteric cases were reported.
Historically, prevention of HAV infection has relied on hygienic standards and immunoglobulin prophylaxis. However, administration of immunoglobulin has not been cost-effective during large-scale epidemics. HAV vaccines that appear safe and efficacious are available in Europe and recently have been licensed in the United States.
Perspective
Hepatitis A virus (HAV) infection is a major disease problem for Alaska Natives. The disease typically follows a pattern of cyclic recurrences every 10-12 years. The latest statewide epidemic began in late 1986 and ended in 1994. Over 2,500 icteric cases were reported. The recurrence of village outbreaks is dependent on the presence of a young susceptible population.
Historically, prevention of HAV infection has relied on hygienic standards and immunoglobulin prophylaxis. However, administration of immunoglobulin has not been cost-effective in the face of large scale epidemics. In 1993-1994, a trial of one dose of HAV vaccine to nearly 5000 persons in 25 rural Alaska communities halted an established epidemic and has appeared to provide long-term as well as short-term protection.
The focus of AIP's HAV program has been to understand and describe the population of Alaska Natives susceptible to HAV infection and to test candidate HAV vaccines in the population. Testing of banked serum samples from previous statewide serosurveys for antibody to HAV has enabled assessment of susceptibility to HAV infection.
In conjunction with the Indian Health Service (IHS) and SmithKline Beecham Pharmaceuticals, a study demonstrated the usefulness of one dose of vaccine without concurrent immune globulin in an outbreak setting. In addition, a safety and immunogenicity study of hepatitis A vaccine was conducted prior to licensure among Alaska Native preschoolers, adults, and non-Native adults. This study has allowed comparisons of various vaccination schedules in children, examination of potential age trends in response to vaccine in Alaska Native adults, and comparisons of Native adults with non-Native adults. This group has been followed-up for 10 years after vaccination. Continued follow-up will enable assessment of antibody persistence. This vaccine has been licensed for persons 2 years of age and above. The Alaska Native Medical Center (ANMC) and CDC are currently conducting a study of the Immunogenicity of this vaccine in Alaska Native infants.
Control Program for Hepatitis A
The focus of AIP's HAV program has been to understand and describe the population of Alaska Natives susceptible to HAV infection and to test candidate HAV vaccines in the population. Testing of banked serum samples from previous statewide serosurveys for antibody to HAV, through susceptibility to HAV infection, has been assessed. In conjunction with the Indian Health Service (IHS) and SmithKline Beecham Pharmaceuticals, a safety and immunogenicity study of a candidate hepatitis A vaccine (HAVRIX ) has been conducted among Alaska Native preschoolers and adults and non-Native adults.
In this study, various vaccination schedules in children have been compared, potential age trends in response to vaccine in Alaska Native adults have been examined, and results in Native adults have been compared with those in non-Native adults. Long-term follow-up on the study groups will allow antibody persistence to be assessed. Work with the IHS and the state of Alaska focused on demonstrating the usefulness of the vaccine in an outbreak setting.
AIP been involved in the following:
- has participated in the IHS committee to plan a nationwide strategy for control of HAV in Alaska Natives/American Indians. In addition, AIP has assisted IHS and the state of Alaska to develop and implement the introduction of hepatitis A vaccine to all Alaskans 2 to 14 years of age. This unique program was the first in the United States to involve all residents of a state in a hepatitis vaccine control program.
- provided technical assistance and scientific advice to the IHS in its attempt to control the most recent outbreaks of hepatitis A using this vaccine. Data from the earlier statewide serosurvey were used to help make decisions about the need for vaccination in specific age-groups.
- assisted in an IHS study involving the use of hepatitis A vaccine in people with chronic liver disease and other viral hepatitis infections.
- assisting in a collaborative study that began in 1996 between the IHS and the National Center for Infectious Disease's Viral and Rickettsial Diseases, Hepatitis Branch to administer hepatitis A vaccine to infants and young children <2 years of age.
- developed the laboratory capabilities to quantitatively measure anti-HAV.
The hepatitis A working group has responsibility for setting the direction
of efforts to preventing hepatitis A in Alaska Natives, as well as in other
Alaska residents and Native American populations. The statewide hepatitis
A immunization program of 2-year-olds to 14-year-olds will yield information
that will be helpful in designing universal hepatitis A programs elsewhere.
Accomplishments
- AIP provided technical assistance and scientific advice to the IHS in the successful effort to control the most recent outbreaks of hepatitis A using this vaccine. Data from the earlier statewide serosurvey were used to help make decisions about the need for vaccination in specific age-groups.
- AIP has assisted IHS and the State of Alaska to develop and implement the introduction of hepatitis A vaccine to all Alaskans 2 to 14 years of age. This program began in January 1996 and was the first in the United States to involve all residents of a state in a hepatitis A vaccine program. The statewide program will yield useful information that will be helpful in designing universal hepatitis A programs elsewhere.
- AIP is assisting in a collaborative study begun in FY96 between IHS and CDC's DVRD Hepatitis Branch to administer hepatitis A vaccine to infants and young children <2 years of age. Since this age-group is the likely one to quickly transmit the virus throughout the population, finding that this vaccine is safe and effective and can be administered in conjunction with other childhood immunizations in this age group is essential to controlling the spread of this disease.
- AIP assisted in an IHS study involving the use of hepatitis A vaccine in people with chronic liver disease and other viral hepatitis infections. This study provided information demonstrated the Immunogenicity of this vaccine in this subpopulation who may be at risk of more severe disease if they become infected with hepatitis A.
- The HAV vaccine study is providing important data on the safety and immunogenicity of the vaccine in the rural Alaska population. The study assisted in the selection of a schedule for administration of the vaccine, provided data on possible age trends in vaccine response, and helped assess any potential ethnic differences in response to the vaccine. The long-term follow-up of the participants helped in determining the length of time that antibody levels are elevated following vaccination.
- AIP has assisted in an IHS study of administering the second dose of hepatitis A vaccine to children and adults 18 to 30 months after the initial dose.
Future Plans
- Follow the cohorts of study participants who were vaccinated in infancy, during childhood and adulthood to determine the long-term protection provided by this vaccine.
- Continue to develop the laboratory capabilities to measure levels of
antibody to hepatitis A to facilitate long-term Immunogenicity studies.
- Provide consultation to the IHS in its studies of hepatitis A vaccine in children <2 years of age.
- Continue collaboration with the state of Alaska and IHS in evaluating the status of HAV infection in Alaska Natives, and in implementing the statewide vaccination program.
- Evaluate a possible future role in post-licensure studies to assess vaccine implementation strategies and their effect in the rural Alaska population.
