RESUMO
BACKGROUND: We recently developed HOUSES, an individual housing-based socioeconomic status (SES) measurement for health disparities research. We assessed whether HOUSES was associated with risk of pertussis and pertussis vaccine up-to-date status in children. METHODS: The study utilized a previous population-based case-control study cohort assembled during the 2004-2005 pertussis outbreak. We collected data on pertussis vaccine status (up-to-date status) at the time of the index date. Using a z-score for housing value, actual square footage, and numbers of bedrooms and bathrooms, HOUSES was formulated in continuous variable and categorized into quartiles. Vaccine up-to-date status was compared among subjects with different SES as measured by HOUSES using a chi-square test and logistic regression models. RESULTS: Of the 391 eligible pediatric subjects (median age of 13.1 years with male sex of 55 %), 363 (93 %) were successfully geocoded to formulate HOUSES index. HOUSES was not associated with the risk of pertussis (p = 0.82). Pertussis vaccine up-to-date statuses were 79, 86, 83, and 94 % for children in the first (the lowest SES), second, third, and fourth quartiles of HOUSES, respectively (p = 0.03). HOUSES as a continuous variable was associated with pertussis vaccine up-to-date status (adjusted OR: 1.15 per increment of one unit of HOUSES, 95 % CI: 1.04-1.27, p = 0.008). CONCLUSION: While HOUSES is not associated with the risk of pertussis, it predicts vaccine up-to-date status among children with different SES. HOUSES may be a useful tool for vaccine delivery research among children.
RESUMO
BACKGROUND: The recent pertussis outbreak in California highlights the effect of pertussis on public health. In 2004, a pertussis outbreak occurred in Olmsted County, Minnesota, despite a high vaccine uptake. This outbreak provided a natural experiment to assess the relationship between asthma and pertussis. OBJECTIVE: We sought to determine whether asthmatic subjects have a higher risk of pertussis than nonasthmatic subjects. METHODS: We conducted a population-based case-control study. There were 223 pertussis cases identified by means of PCR in 2004 and 2005. We identified age- and sex-matched control subjects from 5537 patients with negative test results for pertussis. We conducted a comprehensive medical record review and applied predetermined criteria to ascertain asthma status. Conditional logistic regression was fit to assess the effect of asthma status on the risk of pertussis. RESULTS: Of the 223 subjects, 164 were eligible for the study, and 328 matched control subjects (1:2 matching) were enrolled. Of these 164 subjects, 50% were male, and 82% were white. The median age at the index date of pertussis was 14 years. Sixty-two (38%) of the 164 cases had asthma before the index date of pertussis compared with 85 (26%) of the 328 control subjects (odds ratio, 1.73; 95% CI, 1.12-2.67; P = 013). The population attributable risk percentage of asthma for risk of pertussis was 17%. CONCLUSIONS: Given the high prevalence of asthma and the ongoing risk of pertussis throughout the United States, consideration of defining asthmatic subjects as a target group for pertussis vaccination (eg, replacing decennial tetanus-diphtheria booster with tetanus, diphtheria, and acellular pertussis vaccine for adolescents and adults) should be given.