The vaccine exemption rate in the Houston Independent School District may still be relatively low, but an interactive breakdown by individual campuses shows a striking thing: most of the highest totals are occurring at high performing schools that serve affluent populations.
As the Chronicle detailed Monday, the number of Texans who exempt their children from vaccination for non-medical reasons rose last year for the 12th straight year. The increase brought the number to nearly 45,000, still less than 1 percent of the state's roughly 5.5 million schoolchildren but 19 times more than the 2003 amount. That was the first year after a new state law allowed parents to decline state immunization requirements for "reasons of conscience."
The numbers aren't high enough to threaten herd immunity, the idea that vaccination of a significant portion of a population provides a measure of protection for those individuals without immunity to a contagious disease. But public health officials fear clusters of "anti-vaxxers" could leave many children vulnerable, particularly those with medical conditions that prevent vaccination and those too young to be vaccinated.