Five Minnesota children have grown sick — and one of them died — from a germ that can cause meningitis, causing U.S. health officials to warn of the importance of a common childhood vaccine.

The Hib vaccine, which is given to babies, has succeeded in reducing U.S. cases of the bacterial illness to about only 20 a year in children younger than 5. But a cluster of five cases occurred in central Minnesota last year in young children. One child, who was 7 months old, died of meningitis in November.

No other states have reported such an increase. But Minnesota's disease surveillance is unusually good, so problems in other states could be developing, said Dr. Anne Schuchat of the U.S. Centers for Disease Control and Prevention.

Three of the five children — including the dead child — had not received any vaccine, due to a decision by their parents. But a shortage of Hib vaccine may also have contributed, CDC officials said.

Haemophilus influenzae Serotype b (Hib) can cause meningitis, pneumonia and other dangers. Because of a Hib vaccine shortage that started in 2007, CDC officials say doctors should defer for most children a booster dose given at 12 to 15 months. But they say there's enough for children to get necessary doses at ages 2, 4 and 6 months.