Pertussis or whopping cough is a contagious respiratory disease that can be life-threatening to newborns and infants. Children are better protected after receiving a 5-dose vaccine series. A new study examined the relationship between pertussis and time since receipt of the fifth dose of the D-TaP vaccination series, after an outbreak of pertussis in children in California. Catherine Dolf has more in this week’s JAMA Report.