Contagious disease's spread highlights dilemma over unvaccinated kids

An old childhood disease reared its head in Minnesota last year, infecting five young children and killing one of them, according to a recent report by the Centers for Disease Control and Prevention. The outbreak, of a disease known as "Hib" for short, is the latest of several contagious diseases making encore appearances after having been all but vanquished through immunization. Although the Hib outbreak was small, public health officials worry that parents opting not to vaccinate their children -- or delaying until kids enter school -- may put more communities at risk for similar outbreaks in the future.

Haemophilus influenzae type b (Hib) is a bacterial disease that can cause serious and sometimes fatal illness in children younger than 5. Hib was once the leading cause of bacterial meningitis, an infection that can lead to brain damage and deafness. The bacterium can infect other tissues as well, causing complications such as pneumonia, serious blood infections or severe swelling in the throat. In its less invasive form, Hib also used to be the most common cause of ear infections in children.

Before vaccines against Hib became widely available in the early 1990s, an estimated 20,000 children in the U.S. were seriously sickened by Hib each year and nearly 1,000 died. Since then, it has virtually disappeared. "Haemophilus influenzae type b was the most important bacterial disease that we encountered in pediatrics for half of my career as a pediatrician," says Dr. Wilbert Mason, who heads the division of infectious diseases at the USC Keck School of Medicine.

No cases of Hib have been observed in Los Angeles in 2008 or so far this year, says Dr. Jonathan Fielding, director of public health for Los Angeles County. But, he adds, "I am concerned that over time this will be an increasing problem." That is because an increasing number of parents are obtaining exemptions from school vaccination requirements.

The disease may be practically gone, Mason says, but "the organism is still around."

The CDC report, published Jan. 30, noted that in three of the five Minnesota cases, children had not been vaccinated against Hib. (The other two cases were of a child who hadn't completed the full series of shots and a child with immunodeficiency.) The outbreak happened to occur when vaccine supplies were low, but the shortage did not prevent any of the five from being immunized, the report said