how long does a cough last in infants?
<answer> Whooping cough can last up to 3 weeks. <context> Español: Signos y síntomas. Pertussis (whooping cough) can cause serious illness in babies, children, teens, and adults. Symptoms of pertussis usually develop within 5 to 10 days after being exposed, but sometimes not for as long as 3 weeks.