Societal Costs and Morbidity of Pertussis in Adolescents and Adults. Lee GM, Lett S, Schauer S, LeBaron C, Murphy TV, Rusinak D, and Lieu TA, for the Massachusetts Pertussis Study Group. Clinical Infectious Diseases 2004;39:1572-1580.
Explanatory note: Pertussis or whooping cough is a bacterial infection caused by Bordetella pertussis. Pertussis causes severe coughing spells and is most severe when it occurs early in life. Routine immunization of infants and young children with pertussis-containing vaccines in the 1940s led to a dramatic decline in the number of cases and deaths due to pertussis.
However, pertussis cases among adolescents, adults and young infants began to increase during the 1980s and 1990s. In 1997, adolescents and adults accounted for 46% of reported cases of pertussis; they may spread the infection to young infants who are too young to benefit from vaccination and who have the greatest risk of severe consequences of infection. This has prompted consideration of booster pertussis immunizations for older age groups.
For more than a decade, Massachusetts has employed a unique enhanced surveillance system to detect cases of pertussis among its population, offering free diagnostic testing to patients and the health care professions.
What are the medical and non-medical costs associated with whooping cough in adolescents and adults?
The researchers identified adolescents—10 to 17 years of age—and adults—18 years of age and older—with confirmed whooping cough in Massachusetts between 1998 and 2000. They then evaluated the direct medical costs incurred by these people, including outpatient and hospital-based medical services.
Additionally, the researchers estimated nonmedical costs and the severity of the disease through interviews with persons who had whooping cough from December 2001 through January 2003. The interview included questions about the type and duration of symptoms, time missed from work or school, personal time missed, and other out-of-pocket costs, such as those for transportation to doctor visits, for babysitting, and for over-the-counter medications.
Medical and nonmedical costs were adjusted to 2002 US dollars.
This study identified 1,679 cases of whooping cough in adolescents and 936 in adults. Disease severity was worse in adults than in adolescents.
The mean medical cost per case in adolescent and adult patients was $242 and $326, respectively—mostly from physician visits and antibiotics. Medical costs were significantly higher in adults than adolescents, in patients who had not received vaccination during childhood or had an unknown vaccination status, and in patients who developed severe cough illness or pneumonia.
The average nonmedical costs per case for adolescents and adults were $155 and $447, respectively. The majority of these costs were a consequence of loss of work time for adults and for parents of adolescents with pertussis.
Societal costs of whooping cough in adults and adolescents were found to be $397 and $773. Had the investigators included the costs of treating contacts with antibiotics, the costs would have been $1952 and $804. Costs for public health interventions were not assessed.
Whooping cough causes significant morbidity and is a costly illness among adolescents and adults.
Severe coughing illnesses in adults and adolescents have increasingly been recognized to be caused by B. pertussis and these individuals may contribute to the transmission of infection to infants too young to benefit from being immunized. This study evaluates the morbidity and societal costs of pertussis in these older groups which will be helpful in considering potential vaccine use in these age groups.