Resurgence of rare disease leads to warning: Vaccinate

An unexpected resurgence of a rare but dangerous childhood illness has prompted Minnesota health officials to issue a public warning for parents to make sure their children are fully vaccinated.

Five cases of the infectious children's bacterial disease known as HiB, or Haemophilus influenza type B, were reported in Minnesota in 2008, the most since a vaccine was introduced in the early 1990s, state health officials said Friday.

One of the five children who got sick died, becoming the first HiB fatality in Minnesota since 1991. That child, and two others, had not been vaccinated, health officials said.

"It's really important that parents stay on top of the vaccinations," said Ruth Lynfield, the state epidemiologist. "HiB is a very dangerous infection, but there is an effective vaccine that has been in use for almost 20 years."

HiB, which is different from the more common viral influenza, is an invasive bacteria that can infect joints, bones and the bloodstream, leading to meningitis, pneumonia and death.

But it's a disease that had been nearly wiped out across the United States after a vaccine that is given to babies in the first months of life was introduced in the early 1990s.

No more than one or two cases had been reported annually in young children in Minnesota since then, said Kris Ehresmann, immunizations program manager for the Minnesota Department of Health.

Ehresmann said the number of cases reported in Minnesota last year may also have jumped in part because of a shortage in the supply of the vaccine dating back to November 2007.

Dr. Anne Schuchat, head of immunization at the federal Centers for Disease Control and Prevention, said Friday that the increase in Minnesota cases in 2008 was "very unusual" and something the CDC has not seen elsewhere.

She said she doesn't know if similar spikes are occurring in other states, in part because Minnesota does a better job than most states in disease surveillance.

"What we're concerned about now is the uptick in Minnesota and making sure parents realize the bacteria is still around and their children need to be vaccinated," she said.

Unrelated cases

The Minnesota children diagnosed with HiB in 2008 ranged in age from 5 months to 3 years.

Lynfield said there was no connection between any of them -- one victim lived in the metro area, the others lived in different counties in central Minnesota.

Three children, including the 7-month-old who died, had not been immunized because their parents did not want them vaccinated, she said.

Typically, children receive the vaccine in a series of two or three shots by the time they are 6 months, when they are considered at risk for the disease. They also receive a booster shot at 12 to 15 months.

Ehresmann said a review of state immunization registry data for 2008, however, showed that nearly 1 in 5 children didn't receive all of the shots, even though they stayed on schedule for immunizations against other diseases. That suggested that some doctors may have had trouble getting the needed vaccine.

Ehresmann said that Merck, a manufacturer that produced the vaccine most often used by doctors in Minnesota, voluntarily recalled it at that time out of concern that it might be contaminated. That vaccine has not been available since.

Although other manufacturers continue to produce vaccine, the shortage of the Merck product over the past year meant that some infants in Minnesota were not completing their vaccinations.

Lynfield said state health officials are now working with the CDC and Sanofi-Pasteur, a vaccine manufacturer, to receive an additional 37,000 doses in coming months to ensure that every child can be vaccinated.

"This vaccine is the best tool in our tool box to protect from this infection," Lynfield said. "And it can be a horrible infection. ... If there's one lesson we can take away from this, it's really trying to be sure people understand the important role the HiB vaccine has in preventing this disease."

Richard Meryhew • 612-673-4425