ABSTRACT
BACKGROUND: Between September and December 2003, an outbreak of pertussis occurred in Cass County, MO, mostly among adolescent school children. METHODS: We conducted a 1:2 matched case-control study among school children and used conditional logistic regression to evaluate risk factors for pertussis, including the total number of vaccine doses received, age at administration of each dose of vaccine and the type of vaccine (whole cell or acellular). RESULTS: Of all 127 pertussis cases reported in this outbreak, the majority were adolescents (10-19 years of age, 50%) and adults (20 years or older, 22%); only 10% were infants and children less than 5 years of age. Because the focus of our investigation was on school-aged children, we enrolled 237 students (79 cases and 158 controls) in our study. Students missing at least one dose of the vaccine had higher risk for pertussis than those who received all 5 doses (odds ratio [OR], 2.36; 95% confidence interval [CI], 1.17-4.77). Early administration of the fifth dose of the vaccine at age 4 years was significantly associated with risk for pertussis compared with vaccination at age 5 years (adjusted OR, 2.45; 95% CI, 1.16-5.16). A short time interval (<36 months) between the fourth and fifth doses of the vaccine also tended to increase the risk for pertussis, although this association was not statistically significant. The type of vaccine was not a significant risk factor. CONCLUSION: Administering all 5 doses of pertussis vaccine and the fifth dose at age 5 years with at least 36 months between the fourth and fifth doses provided the best protection against pertussis among children and adolescents in this outbreak.
Subject(s)
Disease Outbreaks , Pertussis Vaccine , Vaccination/statistics & numerical data , Whooping Cough/epidemiology , Whooping Cough/immunology , Adolescent , Adult , Age Factors , Case-Control Studies , Child , Child, Preschool , Female , Humans , Immunization Schedule , Infant , Logistic Models , Male , Middle Aged , Montana/epidemiology , Pertussis Vaccine/administration & dosage , Risk Factors , Time Factors , Treatment RefusalABSTRACT
OBJECTIVES: This research was designed to evaluate the impact on health departments of the implementation of a 1999 policy requiring hepatitis B (HBV) vaccination for seventh grade school entry in the state of Missouri. METHODS: The authors employed a retrospective descriptive design using data from the Missouri Health Strategic Architectures and Information Cooperative (MOHSAIC) system. They based their assessment of the impact of the new policy on six outcome variables: total immunizations administered, HBV immunizations administered, HBV immunizations given to children ages 10 to 14, percentage of total immunizations that were HBV, percentage of total HBV immunizations that were given to children ages 10 to 14, and percentage of total immunizations that were HBV given to children ages 10 to 14. Outcome variables from the months of July through September 1998 were compared to similar data from the same period in 1999. RESULTS: Statewide, there was a significant increase in all outcome variables. Health departments in non-rural settings, however, did not have a significant increase in total immunizations (t = -1.49, p = 0.158). The number of HBV immunizations did increase at health departments where alternative strategies (e.g., school-based programs) were used, but the increase was not as dramatic as for sites where no such strategies were employed. CONCLUSIONS: Implementation of a state policy requiring additional immunizations can be expected to have a significant impact on the resources of health departments statewide. The use of alternative strategies for managing immunizations outside the traditional health department setting can limit that impact.