Public health officials credit greater awareness, faster diagnosis and a new state law requiring that middle and high school students get a booster shot.
The news Tuesday comes after the state experienced a whooping cough epidemic in 2010 in which 9,000 people were infected and 10 infants died.
Though infections remained high last year, no deaths were reported.
Dr. Gil Chavez of the state Department of Public Health says authorities are waiting to see how this year goes before declaring the epidemic over. But he says the state is headed in the right direction.