California is seeing the number of pertussis, or whooping cough cases at levels not seen in several years, and it’s likely to increase, according to a  California Department of Public Health (CDPH) press release yesterday.

Public domain image/National Atlas of the United States
Public domain image/National Atlas of the United States

The CDPH says they have received reports of 2,649 cases of pertussis occurring from January through May 27, 2014, more than the number of cases reported in all of 2013. More than 800 cases were reported in April alone, the highest monthly count since the 2010 epidemic.

California’s “Top Doc” expects this trend to continue. “The number of pertussis cases is likely to continue to increase,” says Dr. Ron Chapman, CDPH director. “As an important preventive measure, we recommend that pregnant women receive a pertussis vaccine booster during the third trimester of each pregnancy, and that infants be vaccinated as soon as possible.”

Infants too young to be fully immunized remain most vulnerable to severe and fatal cases of pertussis. Sixty-six of the hospitalized cases to date in 2014 have been in children four months of age or younger. Two infant deaths have been reported this year, one with onset in 2013, the second with onset in 2014.

Eighty-three percent of the cases have occurred in infants and children younger than 18 years of age. Of the pediatric cases, 8 percent who were younger than 6 months-old and 70 percent were 7 through 16 years of age, health officials note.

Related: 2012 U.S. pertussis outbreak is worst in decades

Whooping cough is caused by the bacterium, Bordetella pertussis. This vaccine-preventable disease is spread through direct contact with respiratory discharges via the airborne route.

Pertussis goes through a series of stages in the infected person; initially an irritating cough followed by repeated, violent coughing. The disease gets its nickname by coughing without inhaling air giving the characteristic high-pitched whoop. Certain populations may not have the typical whoop like infants and adults.

It is highly communicable, especially in very early stages and the beginning of coughing episodes, for approximately the first 2 weeks. Then the communicability gradually decreases and at 3 weeks it is negligible, though the cough my last for months. For more infectious disease news and information, visit and “like” the Infectious Disease News Facebook page.

Those that are not immunized are susceptible to this disease. Young infants and school aged children (who are frequently the source of infection for younger siblings) are at greatest risk.

To prevent pertussis, CDPH recommends that pregnant women receive a pertussis vaccine booster during the third trimester of each pregnancy, even if they’ve received it before,                  
infants be vaccinated against pertussis as soon as possible. The first dose is recommended at two months of age but can be given as early as 6 weeks of age during pertussis outbreaks. Children need five doses of pertussis vaccine by kindergarten (ages 4-6),  California 7th grade students receive the pertussis vaccine booster as required by state law and adults receive a one-time pertussis vaccine booster, especially if they are in contact with infants or if they are health care workers who may have contact with infants or pregnant women.