A childhood illness that has mostly been curbed through vaccinations has killed one child and sickened four others in Minnesota, officials at the Centers for Disease Control and Prevention said Friday.

The children were infected with the Hib bacteria (Haemophilus influenzae type b). Five cases included three meningitis cases, including the child who died and one case of pneumonia. According to the CDC, these are the highest number of Hib cases recorded since 1992, when the vaccine for Hib was first introduced. The last recorded death from Hib was in 1991. Three of the Minnesota cases occurred in children whose parents chose not to immunize their children.

"The situation is of concern," said Dr. Anne Schuchat, director of the National Center for Immunization and Respiratory Disease at the CDC. "It could be happening elsewhere, and of course it's tragic that one of the children actually died from a preventable disease."

The vaccine shortage may have played a role in flagging immunity among children, the experts said.

"We've had [vaccine] supply problems during the last year with one U.S. manufacturer of the vaccine," said Dr. Schuchat.

But pediatrician Dr. Sue Hubbard emphasizes that there is enough vaccine to immunize the primary series, normally given at 2, 4 and 6 months of age.

CDC officials are urging parents and health-care providers to ensure that infants finish their primary series of shots.

"It is of concern that if we continue to have a shortage of vaccine that children will not get a booster dose and this will affect the 'herd' immunity and then we will see more carrier states of H. flu and therefore ultimately more disease," said Dr. Hubbard.

Dr. Hubbard says Hib primarily affects infants and children under the age of five. The vaccine prevents pneumonia, epiglottis (severe throat infection) and meningitis.

"Bottom line," said Dr. Hubbard, "get your infant immunized as there is risk of disease and death and the vaccine works!"