Federal health officials said more than 21,000 people got whooping cough last year, the highest number since 2005 and among the highest totals in the last 50 years.

The Centers for Disease Control and Prevention reports that California was hit especially hard, with about 8,300 cases reported, including the death of 10 babies.

The disease is very contagious and in rare cases can be fatal, especially for babies too young to be vaccinated. Whooping cough starts like a cold but leads to severe coughing that can last for weeks.

Health experts said they are not sure why there has been such a recent spike in cases of Pertussis, as the vaccine for the disease remains highly effective in children.

The Advisory Committee on Immunization Practices recommends the vaccine for all adults who are around infants.

Photo Credit: James Gathany, CDC