By Terry Kerr Holten, M.D.

Six children have died of whooping cough (also called pertussis) in Ohio since 2001, according to information released by the Ohio Department of Health (ODH). Five of the six fatalities occurred in infants under 12 months of age; three of these were too young to have received any vaccinations. The sixth fatal case of pertussis occurred in a 10-year-old who had received no immunizations. The most recent death occurred in January 2008 in a four week old infant.

Vaccines to prevent whooping cough became widely available in the 1940s, and have been very effective in reducing the incidence of pertussis by more that 80%. Infants and children routinely receive immunization against whooping cough beginning at 6 to 8 weeks of age, as a component of the DTaP vaccine. The DTaP vaccine also protects against diphtheria (D) and tetanus (T). The last dose of DTaP is given at 4 to 6 years of age, and four doses of DTaP are required prior to school entry.

Unfortunately, the DTaP vaccine does not provide lifelong immunity against pertussis, and most people become susceptible to pertussis within 5 to 10 years after their last dose of vaccine. This means that most adolescents and adults are susceptible to whooping cough.

Whooping cough is caused by a bacteria called Bordetella pertussis, and is spread from person to person through respiratory secretions, primarily coughing and sneezing. Most infants who are diagnosed with pertussis acquired the infection from a family member (parents or siblings) who did not know that they were infected. Infants are often the first family member diagnosed with pertussis because they develop more severe illness and often require hospitalization. In infants under two months of age who develop whooping cough, 1 percent die from the infection.

A major breakthrough in the prevention of whooping cough occurred in 2005 with the licensure of two vaccines effective against pertussis in adolescents and adults. (The DTaP vaccine causes frequent and sometimes severe side effects in older children and adults, and therefore is not recommended for individuals older than age 7.) The new vaccines (sold under the brand names Boostrix and Adacel, and called Tdap for short) contain smaller amounts of pertussis and diphtheria antigens than the DTaP vaccine, and are safe and effective in adolescents and adults.

The Advisory Committee on Immunization Practice (ACIP) recommends that all persons between the ages of 11 and 64 years receive a Tdap vaccine. It is recommended that the Tdap vaccine be given at the routine well-child check-up at 11–12 years of age, along with the other vaccines routinely recommended at that age (meningococcal vaccine and human papillomavirus vaccine ). Older adolescents and adults should receive the Tdap vaccine if it has been more than 2-5 years since their last tetanus/diphtheria (Td) booster (normally given at 11 – 12 years of age).

Vaccination against whooping cough is especially important for adolescents and adults who have frequent contact with infants under 12 months of age. This includes parents of infants and young children, day care providers, and health care workers. Vaccination of these groups of people will reduce the chances that an infant who is too young to be immunized will get whooping cough. Ideally, the Tdap vaccine should be given at least one month before contact with infants begins.

Despite the recommendation of the ACIP in 2005, a recent study by the Centers for Disease and Prevention (CDC) showed that only 2.1 percent of adults 18 to 64 years of age are immunized against whooping cough. Unlike childhood vaccines, there is no law that requires adults to receive vaccinations.

The Clinton County Health Department has offered the Tdap vaccine since 2005. Recently, the ODH distributed a supply of the Tdap vaccine to local health departments to be targeted for use in adolescents and adults who have frequent contact with infants under 12 months of age. Because the vaccine is subsidized by the ODH, the Clinton County Health Department is able to offer the vaccine at a reduced cost ($20). The usual cost of the Tdap vaccine is $50.

Those who are interested in receiving the Tdap vaccine should call the nursing department at 382-7221 for further information.

EDITOR’S NOTE — Dr. Holten, a pediatrician, is medical director of the Clinton County Health Department.