(picture of HIB bacteria cultured on a blood agar plate)
I just read this story in the MMWR (Morbidity and Mortality Weekly Report) which discusses infectious disease as it relates to events in the US. This report is put out by the Centers for Disease Control and is free to anyone interested. Click the link above to check it out.
This time the report describes something that causes me to worry. A group of underimmunized children who contracted invasive HIB disease. This disease affects children the most, and has been nearly a non-issue since the HIB vaccine became available in the US. The bacteria, Haemophilus influenza type B (which is actually misnamed since it doesn't cause the flu at all), causes respiratory infections including ear infections. It can also cause bacterial pneumonia, meningitis, and epiglotitis (deadly bacterial croup that strikes fear into the heart of folks like me trained in the 80's because it can cause the throat to swell shut suddenly and kill a child very quickly).
So, in December 2007, several lots of HIB vaccine made by Merck company were recalled and the plant that made the vaccine was closed. This resulted in a shortage of HIB vaccine in the US because it left only one manufacturer, Sanofi Pasteur. We're still experiencing that shortage in the US.
Because of the shortage, the CDC has advised health care providers to give only the initial 3 doses of HIB vaccine to infants, and to skip the 4th dose usually given after 1 year of age. Health care providers and the CDC worry that rationing the vaccine like this could cause an increase in invasive HIB disease in the US. So far, we've managed to be lucky.
However, in Minnesota there were 5 cases of invasive HIB during 2008. None of the cases were associated in any way--the families involved lived in different counties and had no relationship to one another. The kids were ages 5 months to 3 years of age. One died.
The one thing they had in common was that they had not completed the first 3 doses of HIB vaccine (so in other words, this could have happened even without a HIB shortage). Three of the children were unimmunized because their parents refused immunizations. One of these children died of their HIB disease. Two of the children only had two doses of HIB. One of those children also had an immunodeficiency condition.
Infectious disease specialists believe that these cases represent an increase in numbers of children who are carriers of the disease. This means that children who are not immunized, or underimmunized, are at greater risk of contracting invasive HIB disease because we are experiencing a breakdown of "herd immunity." If the herd is not completely immunized, more members will be carriers (they harbor the disease but either aren't sick or have milder illness). The unimmunized are then at greater risk of contracting the illness. With no immunity, they have a greater risk of severe illness and death.
Washington State has a large number of unimmunized people, and depending on "herd immunity" has never been a sure bet out here. Shortages like the one we are experiencing with HIB vaccine are a serious threat to the health of our children. We need to consider the implications of the limited supply chain for critical public health infrastructure like vaccines. We can't afford to allow this to happen in the USA. It's actually scandalous, and I'm shocked that there has not been public outcry. I don't think I've even heard it in the news at all.
So, go forth after reading this and let our president know that our children can't be put at risk because of vaccine shortages in the US. Contact your legislators. Spread the word. How can we call our country great if it can't even ensure enough vaccine for the children who need them?
Read more: http://en.wikipedia.org/wiki/Hib_vaccine
and be sure to check the references cited there as well.
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