Hepatitis A Incidence and Hepatitis A Vaccination Among American Indians and Alaska Natives, 1990–2001. Bialek SR, Thoroughman DA, Hu D, Simard EP, Chattin J, Cheek J, and Bell BP. American Journal of Public Health 2004;94(6): 996-1001
Explanatory note: In the past, the incidence of hepatitis A has been much higher among American Indians and Alaska Natives (AIAN) than in the overall population in the United States. An inactivated hepatitis A vaccine was licensed in 1995 and has been recommended for use in children over 2 years of age, in areas of the U.S. with the highest risk of the disease, including AIAN populations.
What has been the effect of hepatitis A vaccination on the incidence of the disease among American Indians and Alaska Natives in the United States?
This study compared the incidence of reported cases of hepatitis A during 1990-1996 (before routine vaccination was implemented for AIAN children) and 1997-2001 (when routine vaccination was being implemented).
The researchers analyzed data on hepatitis A incidence from urban areas where AIAN populations were greater than 10,000 in 1999. They also analyzed similar data from rural reservation communities in Arizona, New Mexico, South Dakota, Montana and Utah.
Additionally, the researchers examined vaccination coverage levels among children of the Navajo Nation, the largest reservation in the United States.
This study found that the incidence of hepatitis A among AIAN declined 20-fold during 1997–2001 while declining 3–fold in the United States overall.
Before hepatitis A immunization was implemented, between 41 and 105 of every 100,000 AIAN people developed hepatitis A every year. In 2001, 5 in every 100,000 AIAN people developed the disease. This decline occurred among AIAN people in both rural and metropolitan areas, although the decline was smaller in urban areas. Most of the decline occurred among children.
The study also found that among a sample of 1,956 children living on the Navajo Nation, 77% had received at least one dose of hepatitis A vaccine, and 52% had completed the vaccine series.
Hepatitis A rates among AIAN peoples declined dramatically with the introduction of routine and catch-up hepatitis A immunization.
Rates of hepatitis A have declined in the United States since introduction of hepatitis A immunization in regions with the highest incidence of disease. Although AIAN children remain at higher risk of hepatitis A disease than the entire population, the introduction of childhood hepatitis A vaccination has reduced the racial disparity in incidence of this disease.