By Suzanne Rostler

NEW YORK (Reuters Health) - Foreign-born children are less likely than their US-born peers to receive immunizations against hepatitis B and a type of bacteria that can cause life-threatening, potentially brain-damaging illness, researchers with the US Centers for Disease Control and Prevention ( news - web sites) (CDC) report.

Their study compared rates of vaccination among US-born and foreign-born children aged19 to 35 months. Parents of youngsters applying for US citizenship are required to have documents that show the child has been immunized. If documentation is unavailable the child is scheduled to receive the first set of required vaccinations.

According to the researchers, children born in other countries were just as likely as US-born children to have the first three shots of the diphtheria, tetanus and pertussis (DTP) vaccine and were also immunized against polio ( news - web sites) and measles. Similarly, foreign-born children were just as likely to receive the single dose of varicella (chickenpox) vaccine, report researchers in the August issue of Pediatrics online.

But foreign-born children were 45% less likely to have a fourth DTP shot and additional shots for measles and polio, which are booster doses required in the US but not in all countries.

The youngsters were "markedly" less likely to get full immunizations for hepatitis B and Haemophilus influenzae type b (Hib).

Hib vaccination protects children from a bacterium that can cause potentially fatal infections such as meningitis, septicemia and pneumonia. Meningitis, an inflammation of the tissues surrounding the brain and spinal cord, can also lead to brain damage.

All US children receive three doses of Hib vaccine at 2, 3 and 4 months of age. Many developed countries provide a fourth dose, or booster shot, during the second year of life.

The study also found that foreign-born children were less likely to be immunized against hepatitis B, a serious liver disease that is transmitted through sexual contact or contact with tainted blood.

It is unlikely that under-immunized children would be a cause of epidemics, since overall vaccination levels in the US are very high, Tara W. Strine, an epidemiologist from the Atlanta, Georgia-based CDC, told Reuters Health. However, the lower coverage combined with crowded living conditions may put these children at greater risk for these diseases.

"Pediatricians and other health care professionals need to be aware of this risk group and make sure that these children catch up," Strine said. "Because of language, economic and other barriers, we must develop creative strategies to protect these children."

Children living in cities with high populations of immigrants, such as New York, northern New Jersey, Los Angeles, Miami and San Francisco may be at particular risk, she and her colleagues note.

SOURCE: Pediatrics online 2002;110.