FRIDAY, Jan. 23, 2009 (HealthDay News) -- Over the past year, five Minnesota children have fallen ill -- one fatally -- with a germ that can cause meningitis, experts at the U.S. Centers for Disease Control and Prevention announced at a Friday press conference.
That's the highest number of cases recorded since 1992, when the vaccine for Haemophilus influenzae Serotype b (Hib) was first introduced, the CDC officials said. The last recorded death from Hib was in 1991.
"This is a situation we are quite disturbed about," said Dr. Ruth Lynfield, the Minnesota state epidemiologist. "The decrease in herd immunity we're seeing is likely related to the vaccine shortage."
"We've had [vaccine] supply problems during the last year with one U.S. manufacturer of the vaccine, Merck," said Dr. Anne Schuchat, director of the National Center for Immunization and Respiratory Diseases.
Lynfield said the five cases included three meningitis cases -- including the child who died -- and one case of pneumonia.
The vaccine shortage may have played a role in flagging immunity among children, the experts said. "Community protection does not appear to be holding right now," Schuchat confirmed.
Because of the shortage, health officials had been deferring booster shots of the vaccine, normally given at 12 to 15 months. The primary series of the vaccine consists of three shots given at 2, 4 and 6 months of age.
But officials are reporting that some infants are not completing this primary series.
CDC officials are urging parents and health-care providers to ensure that infants finish their primary series of shots. They believe there is enough vaccine to cover that need. Schuchat added that she expected that the vaccine supply would return to higher levels by the summer.
"We don't know if the problem is occurring in other states, but we want to heighten awareness among doctors," Schuchat said. "We are trying to find out if the problem is bigger." There's been an 18 percent decrease among 7-month-olds in Minnesota who had completed the primary series of Hib vaccine, the officials said.
Of the five Minnesota cases, one child hadn't completed the primary series of shots, one had a weakened immune system, and in the three other cases -- including the child who died from meningitis in November -- parents had refused the vaccine, the officials said.
The news follows an announcement last November by U.S. health officials that a shortage of vaccine was leading them to monitor Hib infections, one of the most important causes of bacterial illness in young children.
Though federal officials said at the time that they had not yet seen an increase in cases, the stepped-up surveillance was prompted by a disruption in the supply of vaccine that has virtually eliminated Hib (Haemophilus influenzae type b) infections since it was introduced.
Hib infection can cause a variety of illnesses, including meningitis (inflammation of the membranes covering the spinal column and brain), blood stream infections, and pneumonia, according to the CDC. Hib is not a cause of the seasonal flu.
The shortfall was caused by a recall of certain lots of Hib conjugate vaccine, and then the suspension of production by drug maker Merck & Co. in December 2007. Merck originally expected to resume production late last year, but delays pushed that timetable back to the middle of this year, the CDC said in its Nov. 21, 2008, Morbidity and Mortality Weekly Report.
One reason the vaccine shortage hasn't been more serious is that drug maker Sanofi-Aventis also makes Hib vaccine.
Before the introduction of the vaccine, some 20,000 U.S. children would get serious and sometime fatal Hib infections each year, the CDC noted.
For more on Hib disease, visit the CDC.