Philadelphia has reported 5 new cases of children with invasive Haemophilus influenza type b (Hib) disease. Of these 5 children, 2 have died as a result of Hib. Hib is part of the normal vaccine series. Children receive the primary series at 2, 4 and 6 months of age and a booster at 12 to 15 months of age. These five children were all either unvaccinated or under-vaccinated.
This comes on the heels of the 5 cases, including one death, of invasive Hib disease in five Minnesota children. According to the Center for Disease Control (CDC), only one of these five children had completed the 3 shot primary vaccination series, and that child was later diagnosed with an immunodeficiency. Three children were unvaccinated due to parental refusal and the fifth child was only 5 months of age and therefore too young to complete the primary series. The five Minnesota children lived in different counties and had no contact with each other. None of the children attended daycare.
According to the American Academy of Pediatrics, "before vaccination against Hib was available. Hib meningitis killed 600 children a year and infected 20,000. It was the most common cause of bacterial meningitis. Children who survive the disease were often left with mental retardation, seizures or deafness."
These new cases of Hib are perhaps in part due to a decrease in herd immunity. Since 2007 there has been a Hib vaccine shortage because Merck, one of the two manufactures of the Hib vaccine, had to cease production as a result of bacterial contamination. There should still be sufficient vaccine available for all children to receive the 3 shot primary series but the CDC has asked physicians to delay giving the booster shot -- normally given to children between the ages of 12 and 15 months. When majority of the members of a community are vaccinated, the unvaccinated members are safer because the chance of an unvaccinated person coming into contact with the disease decreases. This concept is referred to as herd immunity. However with so many children unvaccinated in conjunction with a national Hib vaccine shortage, unvaccinated children are at an increased risk of infection. This applies not only to children whose parents refuse the vaccine but also to young infants who are simply too young to receive all three shots.
I have often heard parents rationalize delaying vaccination because they are not sending their children to pre-school or daycare. Unfortunately, these parents may be fooling themselves into a false sense of security. As illustrated by all five cases in Minnesota, children can acquire Hib, or any other infectious disease, even if they do not attend a child-care program.
We do not know what causes autism. There have been multiple studies looking for a link between vaccines and autism, but none has been found. Although we do not know what causes autism, we do know what is the number one cause of bacterial meningitis -- Hib. The only way to protect your child from this disease is to vaccinate him against it.
For a very interesting list of vaccine preventable diseases, what these diseases do and how many children died or contracted these diseases prior to vaccines becoming available see the AAP's page "Why Immunize?".