Slide 21. Hepatitis A

 

Let's switch to hepatitis A. When we think about hepatitis A in children, we think about it as quite a self-limited illness. In children less than 6 years of age, the illness is most often asymptomatic in at least 70% of the cases. In the 30% of children who do have symptoms, they tend to be mild, low-grade fever, malaise, and anorexia. When children over 6 years of age acquire hepatitis, they tend to get a more striking illness, and about 70% of them will develop jaundice.

When adolescents or adults acquire hepatitis A, they develop a memorable illness, which very often will last for weeks. Transmission of hepatitis A is very easy, both within the day care setting as well as in the household. Awareness of hepatitis A within a given environment is very often signaled by the presence of a symptomatic adult who has had contact with an asymptomatic child with hepatitis. That symptomatic adult may be the parent of that child or may be a day care worker.

Slide 22. Epidemiology of Hepatitis A

 

Hepatitis A is endemic in many parts of the world, and as a consequence, acquisition of infection with hepatitis A is a concern for the international traveler. The low-risk areas which have been identified, places where it is unlikely to acquire hepatitis A, include Japan, Australia, New Zealand, western Europe, and Scandinavia. In contrast, the high-risk areas include large parts of the world, eastern Europe, Africa, and Asia. Even within the United States, there are several communities in which hepatitis A is endemic, and those that are very striking include Native Americans, Alaskan Eskimos, much of the Hispanic community, and the Hasidic Jewish community.

Slide 23. Hepatitis A Vaccine

 

Slide 24. Hepatitis A Vaccine

 

Hepatitis A vaccine is indicated for children in communities that have high rates of hepatitis A, and this includes any area that has an annual average incidence that is twice the national incidence of hepatitis A. It turns out that the national incidence of hepatitis A is 10 cases per 100,000 population, and so a high-risk area in the United States is considered to have more than 20 cases per 100,000 population. The areas in the United States where this is the case are in the west and far west. The objective of using the hepatitis A vaccine is to achieve a sustained reduction in the incidence of hepatitis A.

There is not only enthusiasm for immunizing communities where the rate of hepatitis A is more than 20 per 100,000 population, but there is also a fair amount of enthusiasm for immunizing areas in which the incidence of hepatitis A is between 10 and 20 per 100,000 population. If we look at those areas we find that, for the most part, they too are in the western United States.

Slide 25. Average Reported Cases of Hepatitis A per 100,000 Population: 1987-1997

 

Slide 26. Average Reported Cases of Hepatitis A per 100,000 Population: 1987-1997

 

This map shows the average reported cases of hepatitis A per 100,000 population for the decade 1987 to 1997, and we see in the deepest orange those areas in which the rate of hepatitis A is more than 20 cases per 100,000 population. Here is a little map of Florida in which we see there are only 2 counties in which the incidence of hepatitis A exceeds 20 per 100,000 population, and in the next deepest orange, there are those counties in which the rate of hepatitis is between 10 and 20 per 100,000 population.