Pertussis vax only good for a year: study

The booster vaccine Tdap (dTpa) wanes rapidly and provides only limited, short-term protection against pertussis when administered to teenagers.

This is the surprise finding from a US study of more than 270,000 children who were followed from infancy to adolescence.

The results, based on 1207 pertussis cases, suggest dTpa may be more effective if administered in anticipation of a local