When I was in medical training, I had the unfortunate experience of participating in the care of a small child who developed a serious bacterial infection caused by common bacterium known as H. influenza, type B.
The young child developed infection of the lining of the brain, known as meningitis, as well as bacterial blood infection. The infection was so severe that it resulted in the child’s death. My sadness over this unfortunate event was deepened by the fact that the child died from a disease which is virtually unheard of in the vaccine era. The child had received none of the recommended age-appropriate vaccines, including the ones that prevent serious infection from H. influenza, type B.
Needless to say, this experience made me passionate about the importance of vaccines.
I recently was asked by the mother of an infant to explain the purpose of routine vaccination. We discussed the many preventable infectious diseases for which safe and effective vaccines exist and the proven role of vaccines in reducing the risk of illness as well as reducing the risk of preventable complications, including death.
I then addressed the topic of herd immunity. This is sometimes a difficult concept to understand, so let me explain it with a story.
Imagine a baby elephant on the African savannah, traveling with a group of older elephants to the water hole. But danger lurks. In the grass are a group of lionesses that are hungry for an easy meal.
The little elephant, if left alone even briefly or allowed to fall behind, will become an immediate target. Fortunately, the older elephants know this. They are big and strong, and each has the necessary skills to fend off a lion attack. They know that as long as the little guy is with the herd, he will be safe.
Farther afield, there’s a young gazelle wandering alone to the water hole. Though just as thirsty as the elephants, he has no natural defenses. The lions attack with deadly consequences.
The same principle holds true for vaccine-preventable infectious diseases. But, instead of lions, we are dealing with bacteria and viruses. We are the herd. As long as we maintain our strength and defenses through vaccination, the susceptible people among us (the young, the elderly, those with impaired immune systems, those not responsive to vaccines and the unvaccinated) are relatively protected.
In this instance, herd immunity is protection by association with other immunized people. It follows, therefore, that the more of us who have been vaccinated, the safer we all will be with regard to vaccine-preventable infectious disease. Herd immunity is not a reason to skip vaccination but rather another strong argument in favor of it.
Dr. Matthew A. Clark is a board-certified physician practicing at the Ute Mountain Ute Health Center in Towaoc.