DPT VACCINE AND ANAPHYLAXIS SHOW "CAUSAL RELATION," IoM
DPT VACCINE AND ANAPHYLAXIS SHOW "CAUSAL RELATION," IoM report released July 3 concludes. The Institute of Medicine committee, convened to study "adverse consequences" of DPT (diphtheria- pertussis-tetanus) found that "the evidence indicates a causal relation" between the vaccine and two adverse events, anaphylaxis and protracted, inconsolable crying. For anaphylaxis, IoM calculates that the excess risk following DPT vaccine is two cases per 100,000 injections, or six cases per 100,000 children given three doses. Anaphylaxis does not appear to be a problem associated exclusively with the pertussis component of the vaccine, the report notes, but could be caused by either the diphtheria or tetanus components as well. The excess risk for protracted crying following DPT immunization is calculated at .1% to 6% for recipients of DPT. In total, the committee evaluated 17 possible adverse outcomes with regard to the DPT vaccine. The report states "the evidence does not indicate a causal relation" between DPT and infantile spasms, "hypsarrythmia (an EEG pattern that is frequently associated with infantile spasm)"; Reye syndrome, and sudden infant death syndrome. In addition, the IoM report concludes that "the evidence is insufficient to indicate a causal relation" between DPT and aseptic meningitis; erythema multiforme or other rash; Guillain- Barre syndrome; hemolytic anemia; juvenile diabetes; learning disabilities and attention deficit disorder; peripheral mononeuropathy; thrombocytopenia; and chronic neurologic damage. Regarding autism, the committee says that there is "no evidence bearing on a causal relation" to DPT. The report does conclude, however, that the "evidence is consistent with a causal relation" between DPT and acute encephalopathy, as well as shock and "unusual shock-like state." The risk range calculated by IoM is 0 to 10.5 per one mil. immunizations, or 0 to 31.5 per mil. children given three doses of DPT. Evidence is insufficient to calculate excess risk for permanent neurologic damage, the report states. Project director Christopher Howson, PhD, said a meta-analysis of well-controlled studies shows that the range of excess risk for acute encephalopathy following DPT immunization is consistent with that reported by a large, case-controlled study conducted in Great Britain, the National Childhood Encephalopathy Study. The report also concludes that published research supports a causal relation between the currently used rubella vaccine, RA 27/3, and acute arthritis. Research is also consistent in supporting a causal relation between rubella and chronic arthritis, IoM said. For recipients of rubella immunization, acute arthritis "incidence rates are estimated to average 13% to 15% among adult women following RA 27/3 immunization with much lower levels noted among children, adolescents and adult men," the IoM report states. With regard to chronic arthritis in adult women, the evidence "is limited in scope and confined to reports from one institution," the report states. "Prospective, double-masked, controlled trials in which subjects are followed for at least 12 months after rubella vaccination are needed to establish this biologically plausible relation." The report was sponsored by the National Institute of Allergy and Infectious Diseases in reponse to a Congressional directive included in the 1986 National Childhood Vaccine Injury Act. The 11-member IoM committee that prepared the report was chaired by Harvey Fineberg, MD/PhD, Harvard School of Public Health. Stephen Cochi, MD, chief of the National Centers for Disease Control's Infant Immunization Section, commented that the eligibility rules for the vaccine injury table, established under the 1986 Act, "now are written in favor of compensation," and include adverse events not scientifically linked to vaccine injury, such as sudden infant death syndrome and DPT. Cochi predicted that the IoM report, in combination with a statement recently released by the American Academy of Pediatrics (AAP), and an upcoming statement to be published next month by CDC's Immunization Practices Advisory Committee, will encourage the National Vaccine Program to consider altering sections of existing law explaining and defining conditions that can be considered evidence of vaccine injury. An AAP statement on pertussis released May 16 notes that, "while the data accumulated to date may not prove that pertussis vaccine can never cause brain damage, they indicate that if it does so, such occurrences must be exceedingly rare. Furthermore . . . in individual cases the role of pertussis vaccine and acute neurological disease resulting in brain damage is impossible to determine on the basis of clinical or laboratory findings."
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