In an era when vaccines are heavily scrutinized, two pieces of vaccine news may have parents thinking about how and when to vaccinate their kids. News that meningitis has killed one Minnesota child and sickened four others has resulted in the Centers for Disease Control and Prevention reminding parents to get their children vaccinated against Haemophilus influenzae type b. The Hib vaccine, as it is commonly known, is recommended for all kids under 5 years old and is usually given to babies starting at 2 months old. It prevents meningitis, pneumonia, epiglottitis (severe throat infection), and other serious infections.
There has been a shortage of these vaccines since Merck & Co. recalled its Hib vaccines in 2007 because of equipment sterilization problems, but that was not the reason for the Minnesota outbreak, says CDC spokesperson Curtis Allen. Three of the children involved had not been vaccinated because of parental concerns about the vaccine; another child had gotten two out of three required doses (and hadn't yet reached the age necessary for the third dose); and the last child had an immune system disorder that was previously unknown.
The vaccine shortage is ongoing, Allen said, but "there are adequate products available for primary doses" of the vaccine—meaning kids should still be vaccinated using the Hib product made by Sanofi Pasteur, which involves a series of shots given at 2, 4, and 6 months of age. But there is not currently enough supply available to provide booster shots, usually given when children are 12 to 15 months old. "Hopefully, this will be rectified sometime during the middle of the year," when Merck's vaccine is expected to re-enter the U.S. market, Allen said.
In related news, a new study funded by the CDC and published in the February issue of the journal Pediatrics affirms that vaccines containing the mercury compound thimerosal do not seem to harm kids. In 2003, researchers evaluated the development of more than 1,400 children who were vaccinated against pertussis (whooping cough) a decade earlier with vaccines containing two different amounts of thimerosal. The researchers found no significant association between the vaccines and developmental problems. While poorer scores on 2 out of 24 outcomes measured were associated with higher exposure to thimerosal, the findings were based on small differences and may be due to chance.
The study, which confirms the findings of previous research, should reassure some parents who feared the mercury compound might cause autism. "The overall vaccine schedule for children [now] contains 98 percent less thimerosal than it used to—[and] some children get no thimerosal at all in their vaccines," says John Iskander, associate director for science with the CDC's immunization safety office. The children evaluated in the study were vaccinated at a time when vaccines contained higher amounts of thimerosal than today's vaccines, so "this provides us with reassurance" that even then, "they were not receiving developmental harm" because of the vaccines, Iskander said.