Nov. 9, 1999 (Seattle) -- Hospitals can greatly increase the chance that inner-city children will receive all of their childhood vaccinations by providing the first one shortly after birth, according to a study in the Nov. 10 Journal of the American Medical Association.
"Children in the inner city have very low immunization rates," Diane Lauderdale, PhD, an author of the study, tells WebMD. Lauderdale, an epidemiologist at the University of Chicago, says, "I think this may help us improve those rates."
She led a team of researchers who studied over 1,100 children born to residents of the Robert Taylor Housing Development, a public housing project in Chicago. The researchers found that those who received a hepatitis B vaccination shortly after birth were much more likely than other children to receive all their vaccinations on time.
"What we hypothesize is that there is an education component in receiving the first dose in the hospital," she says. That's because hospitals usually have staff members who explain to new mothers not only the reason for the hepatitis B vaccine, but also why children need vaccines for a range of other diseases, ranging from tetanus to diphtheria.
The researchers focused on hepatitis B because it was added to the list of recommended childhood vaccines in 1991. That year, a small number of children born in the housing project were vaccinated for the disease, which is easily passed from mother to infant and can cause fatal liver disease. By 1995, more than half of the children born in the housing development were being vaccinated.
But Lauderdale says the study's most surprising finding was that more than 70% of children who got their first hepatitis B vaccination at birth went on to get all three doses needed to fully protect them. That compares with about half of infants who got their first vaccination when they were between 1 and 3 months old, and around 10% of infants first vaccinated when they were even older.
Similarly, 60% of children vaccinated for hepatitis B at birth received their first vaccines for diphtheria, tetanus, and pertussis (DTP) on schedule, compared with approximately 36% of other children.
Neal Halsey, MD, director of the Institute for Vaccine Safety and a faculty member at Johns Hopkins University in Baltimore, says the Chicago study suggests that giving the first dose of hepatitis B vaccine in the hospital "helps influence parents to complete the series and seek other vaccinations on time." But he says more studies are needed to be certain that this is the case.
In the meantime, Halsey says he fears that hepatitis B vaccination rates may decline because of public concern that the vaccine exposes infants to dangerous levels of mercury. The concern arose because, in the past, hepatitis B vaccines were preserved with a substance called thimerosal, which contains small amounts of mercury.
But Halsey says that only very small babies, such as those born prematurely, run any risk of exceeding governmental limits on mercury exposure due to hepatitis B vaccination. And this issue is about to disappear, he says, because the major vaccine makers are switching to preservatives that contain no mercury, or levels so low they pose no threat.