Who is most at risk for pertussis or whooping cough?
A new born infant has no immunity to whooping cough, and can get it any time after birth if they are not immunized. Most cases of whooping cough occur in children under five years of age. In some cases, older children and adults may also be affected. Young infants are at the highest risk for acquiring clinical pertussis, and for associated complications (for more on complications see http://www.cdc.gov/nip/publications/pink/pert.pdf ).
