RESUMEN
BACKGROUND: Intramuscular interferon beta-1a (IFNß-1a), a multiple sclerosis (MS) therapy that has been commercially available for over a decade, provides a unique opportunity to retrospectively assess postmarketing data for evidence of malignancy risk, compared with relatively limited data available for more recently approved therapies. Postmarketing and claims data were analyzed to determine the risk of malignancy in MS patients treated with intramuscular IFNß-1a. MATERIALS AND METHODS: The cumulative reporting rates of suspected adverse drug reactions coded to malignancy in the intramuscular IFNß-1a global safety database were compared with malignancy incidence rates in the World Health Organization GLOBOCAN database. In addition, using data from a large US claims database, the cumulative prevalence of malignancy in MS patients treated with intramuscular IFNß-1a was compared with non-MS population controls, MS patients without intramuscular IFNß-1a use, and untreated MS patients. Mean follow-up was approximately 3 years for all groups, ie, 3.1 years for the intramuscular IFNß-1a group (range 0.02-6.0 years), 2.6 years for non-MS population controls (range 0-6.0 years), 2.6 years for the intramuscular IFNß-1a nonuse group (range 0.01-6.0 years), and 2.4 years for the untreated MS group (range 0.01-6.0 years). RESULTS: An estimated 402,250 patients received intramuscular IFNß-1a during the postmarketing period. Cumulative reporting rates of malignancy in this population were consistent with GLOBOCAN incidence rates observed within the general population. The claims database included 12,894 MS patients who received intramuscular IFNß-1a. No significant difference in malignancy prevalence was observed in intramuscular IFNß-1a users compared with other groups. CONCLUSION: Results from this evaluation provide no evidence of an increased risk of malignancy with intramuscular IFNß-1a use.
RESUMEN
BACKGROUND: Pertussis is among the most poorly controlled bacterial vaccine-preventable diseases in the United States. In 2006, a tetanus, reduced-dose diphtheria, and acellular pertussis (Tdap) booster was recommended for adolescents and adults. Tdap vaccines were licensed on the basis of antibody response without vaccine effectiveness data. METHODS: From 30 September 2007 through 19 December 2007, a pertussis outbreak occurred at a nursery through twelfth grade school on St. Croix, US Virgin Islands. We screened all students for cough and collected clinical history, including Tdap receipt. Coughing students were offered diagnostic testing. We defined clinical case patients as students with cough 14 days in duration plus either whoop, paroxysms, or post-tussive vomiting, and we defined confirmed case patients as students with any cough with isolation of Bordetella pertussis or those with clinical cases and polymerase chain reaction or serological evidence of pertussis; other clinical cases were classified as probable. RESULTS: There were 51 confirmed or probable cases among 499 students (attack rate, 10%). Disease clustered in grades 6-12, with a peak attack rate of 38% among 10th graders. Of 266 students aged 11 years with complete data, 31 (12%) had received Tdap. Forty-one unvaccinated students (18%) had confirmed or probable pertussis, compared with 2 (6%) of the vaccinated students (relative risk, 2.9); vaccine effectiveness was 65.6% (95% confidence interval, -35.8% to 91.3%; P = .092). CONCLUSIONS: This first evaluation of Tdap vaccine effectiveness in the outbreak setting suggests that Tdap provides protection against pertussis. Increased coverage is needed to realize the full benefit of the vaccine program. Serological testing was an important tool for case identification and should be considered for inclusion in the Council of State and Territorial Epidemiologists case definition.
