Pertussis Activity Spiking in Several States

An outbreak of pertussis has been declared an epidemic by the California Department of Public Health. The agency said that as of June 15, the state had 910 reported cases -- four times more than at the same time last year -- and 600 potential cases were being investigated.

Five infants have died of the disease, commonly known as whooping cough, in California this year, according to the state's health department.

The CDC said June 25 that as of June 19, 5,120 cases of pertussis had been reported nationwide. Although that number was less than the 6,326 reported at the same time last year, several states reported significant increases in pertussis activity, including Texas (1,154 cases), Ohio (523 cases), Michigan (380 cases) and Arizona (163 cases).

In addition, the South Carolina Department of Health and Environmental Council issued a public health advisory (3-page PDF; About PDFs) June 8, saying reported pertussis cases were above an epidemic threshold. The state agency said that in the first 20 weeks of 2010 there were 81 confirmed or probable cases of pertussis, which doubles the number of cases reported during the same period during each of the previous three years. The department said the case total was above an epidemic threshold because it was two standard deviations above the annual mean.

South Carolina had 134 cases of pertussis as of June 25, according to the CDC.

In the news release on the California outbreak, Mark Horton, M.D., M.S.P.H., director of the California Department of Public Health, urged parents to vaccinate their children. He also said that parents, family members and caregivers of infants should get booster shots.

The CDC’s Advisory Committee on Immunization Practices, or ACIP, and the AAFP recommend (1-page PDF; About PDFs) that children receive five doses of diphtheria, tetanus, and pertussis, or DTaP, vaccine, including a primary series at 2 months, 4 months and 6 months. Additional doses should be given at 15-18 months and 4-6 years.

However, the California Academy of Family Physicians posted a recommendation on its website for members to use an accelerated DTaP infant schedule -- initial vaccination at 6 weeks of age with subsequent doses recommended at four-week intervals -- during the outbreak.

More than half of infants less than 1 year of age who get the disease must be hospitalized, according to the CDC. The agency also said one in 20 infants with pertussis get pneumonia.

The CDC said many infants are infected by older siblings, parents or other caregivers who don't even realize they have the disease, which is difficult to diagnose.

A single dose of tetanus, diphtheria and pertussis, or Tdap, vaccine is recommended for adolescents (1-page PDF; About PDFs) aged 11-18 years old and adults (4-page PDF; About PDFs) aged 19-64 years old.

The CDC said protection received from DTaP, the childhood vaccine, fades over time, so adolescents and adults should receive Tdap even if they were vaccinated as children. The agency also said only 2 percent of adults received Tdap from 2005 through 2007.

The CDC issued the following recommendations for physicians June 30.

In addition to the recommendation for an accelerated DTaP infant schedule, the California Academy of Family Physicians posted the following recommendations (1-page PDF; About PDFs) for physicians on its web site.

California’s health department said in its news release that the state is on pace to suffer the most illnesses and deaths due to pertussis in 50 years. In 2005, California recorded 3,182 cases and eight deaths from pertussis, which peaks every three to five years.

More than 25,000 cases were reported nationally in 2005, which was the last peak year. However, the CDC said the actual number of illnesses likely was significantly higher because of cases that were not diagnosed or not reported.