Measles outbreak in an immunized school population. [Authors reply] [letter]

This letter about a measles outbreak in Corpus Christi Texas secondary schools makes 3 points: 1) school records of immunication are only as good as the weakest link in the chain. For example physicians should not consider parents history evidence of vaccination. 2) Paradoxically current improved record-keeping may decrease immunization coverage. This is because in the 1970s inadequate records caused the child to receive a second dose of vaccine but todays more extensive records will lower the incidence of backup shots. 3) Some countries such as Sweden have decided that a 2-dose schedule is cost-effective. For many public health programs the real cots and benefits are measured in public confidence not dollars.