California has seen a doubling of whooping cough infections in the first three months of this year as compared to what was seen in 2009 (219 vs 119, respectively). There have been two deaths of infants from the infection already this year. This infection (caused by Bordetella pertussis) is more severe in infants and children than adults. From the CDC:
Pertussis is worse for very young children; more than half of infants less than 1 year of age who get the disease must be hospitalized. About 1 in 10 children with pertussis get pneumonia (lung infection), and about 1 in 50 will have convulsions.
Adult infections are generally milder and individuals may not even know they are infected. However, they can be carriers/transmitters of disease to younger children. According to the California report:
most cases of whooping cough in infants under six months come from the mother. The public health department recommends that all parents be given the vaccine before leaving the hospital with a new baby.
Boosters are necessary every 10 years. In an outbreak of whooping cough that is occurring in Minnesota, 46 elementary students have developed the disease, with the highest rate in the fifth and sixth grade levels. Most of these students have been vaccinated with the TDaP vaccine, but they are due to have a booster in 7th grade. Officials are wondering if the increasing number of infections at the fifth and sixth grade levels mean that age should be adjusted. (the CDC recommends giving the booster between the ages of 11 and 18).