From the Wall Street Journal, public health officials are concerned about outbreaks in areas that have a higher non-vaccination rate:
Even as more American children are getting immunized against measles, diphtheria and other diseases, public-health officials are increasingly worried about potential outbreaks of these illnesses in certain pockets of the country where vaccination rates are dangerously low.
Parts of Oregon, Washington state, Idaho, Montana and a few other states have some of the lowest rates of compliance with vaccination guidelines—and the problem is growing, health officials say. Overall vaccination rates in some of these communities are under 80%, far below the threshold that is needed to prevent an outbreak for certain diseases. Exemptions in many states for philosophical or religious reasons allow parents to opt out of requirements for children to be vaccinated before entering school. Other parents delay immunizations for their young children, leaving them exposed to possible infections for a longer time.
Do you think that this is a valid concern?