
The History of Vaccines: A Glance Behind and a Look Ahead
A pediatrician evaluates the past and future of kids' inoculations
Continued from page 1In the mid-1980s, a new vaccine technology brought the hemophilus influenza B (HIB) vaccine to the market. At that time, this bacterium was the leading cause of meningitis in children under five in the United States. There were 12,000 cases per year; one-fourth of those children were left with permanent brain damage, and one in twenty died. Today, we have virtually eliminated invasive HIB disease from this country. A similar story is underway with the pneumococcus vaccine introduced in 2000. This germ is now the new top cause of meningitis in small children, but the number of cases has already fallen by over 70 percent.
Clearly, the progress that's been made against these germs has been stunning, with millions of American children saved from debilitation and death over the past 80 years.
Community Immunity
Vaccines are about much more than protecting the individual; there's an equally important benefit with something called "community immunity." The medical establishment can never achieve 100 percent vaccination rates—there will always be those who cannot get protected, either because they are too sick or have weakened immune systems and cannot respond to a vaccine (children with cancer on chemotherapy, for example), or because those children's parents refuse to vaccinate them. These children remain vulnerable to illness; yet if enough of the children in their community are immune, they won't be exposed to these germs as there aren't sick children to pass them along.
To achieve community immunity, over 95 percent of a community needs to be immunized. Thus, childhood vaccinations become more than just a way to keep one child healthy. They are part of a larger social obligation, performed by the healthy and willing for those less fortunate. Another important benefit in having a large portion of the community protected is the prevention of large-scale outbreaks. In 1994, infectious polio made its way to Canada in the form of a traveler from India. Yet because of Canada's high immunization rates, no large outbreak occurred.
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