Immunization rates for hepatitis A in children aged 24-35 months vary widely across areas and populations in the United States, the Centers for Disease Control and Prevention said.
In 1999, the CDC recommended routine immunization against hepatitis A for children residing in 11 states in which the average annual incidence during 1987-1997 was at least 20 per 100,000 population, or twice the national average. Those states are Alaska, Arizona, California, Idaho, Nevada, New Mexico, Oklahoma, Oregon, South Dakota, Utah, and Washington.
They also advised that hepatitis A vaccination be considered in another six states (Arkansas, Colorado, Missouri, Montana, Texas, and Wyoming) where the average incidence was 10-20/100,000 population (MMWR 2005; 54:141-5).
Later this year, the CDC's Advisory Committee on Immunization Practices is expected to discuss broadening these recommendations for the two currently-licensed hepatitis A vaccines, GlaxoSmithKline's Havrix and Merck's VAQTA. Both are inactivated vaccines, given in two doses at least 6 months apart to children aged 24 months and above.
In the first national analysis of hepatitis A vaccination coverage among children, data were collected from provider immunization records for 13,731 children during 2003. In the 11 states in which routine hepatitis A vaccination is recommended, the proportion of children aged 24-35 months who had received at least one dose of vaccine varied from a low of 6.4% (South Dakota) to a high of 72.7% (Alaska).
The overall rate, 50.9%, is below that of other vaccines recommended for routine use in children, the CDC said.
In the six states where hepatitis A vaccination should be considered, 25.0% of children aged 24-35 months had been vaccinated, compared with just 1.4% in the other 33 states with no recommendation. Only two states (Alaska and Arizona) and four urban areas (Maricopa County, Ariz., Los Angeles County, Calif., and Bexar and El Paso Counties, Tex.) had coverage estimates over 60%.
The wide variation in coverage is likely due to targeted programs in some areas. For example, vaccination requirements in Texas border counties for all children attending day care programs probably account for the higher coverage in El Paso County (71%), compared with the rest of the state, the CDC said.
Within the areas where routine hepatitis A vaccine is recommended or should be considered, Hispanic and Native American/Alaska Native children had higher coverage rates that either non-Hispanic white or black children. This finding may be related to greater recognition of the disease among groups that have been identified as high risk.