Bordetella pertussis is the bacteria that causes whooping cough. Coughing or sneezing by an infected person can spread germ-laden droplets into the air, where they are inhaled by anyone nearby. As a child, you receive a whooping cough vaccine that eventually wears off. In an outbreak, most teenagers and adults are susceptible to the infection - and outbreaks continue to occur regularly. Young infants who are not vaccinated or have not received the full set of recommended vaccines are at the greatest risk for severe complications and death.