Differences of IgG antibody avidity after an acellular pertussis (aP) booster in adolescents after a whole cell (wcP) or aP primary vaccination

► Increased IgG-anti-pertussis avidity after adolescent acellular pertussis vaccination. ► Less participants with avidity > 40% after previous whole cell pertussis vaccine. ► Correlation between IgG-anti-pertussis avidity and antibody concentration. ► Correlation between IgG-anti-pertussis avidities before and after booster vaccination. ► Avidity as surrogate marker for pertussis-specific long-term immunity.