Nonhuman animal ("animal") experimentation is typically defended by arguments that it is reliable, that animals provide suffi ciently good models of human biology and diseases to yield relevant information, and that, consequently, its use provides major human health benefi ts. I demonstrate that a growing body of scientifi c literature critically assessing the validity of animal experimentation generally (and animal modeling specifi cally) raises important concerns about its reliability and predictive value for human outcomes and for understanding human physiology. The unreliability of animal experimentation across a wide range of areas undermines scientifi c arguments in favor of the practice. Additionally, I show how animal experimentation often signifi cantly harms humans through misleading safety studies, potential abandonment of effective therapeutics, and direction of resources away from more effective testing methods. The resulting evidence suggests that the collective harms and costs to humans from animal experimentation outweigh potential benefi ts and that resources would be better invested in developing human-based testing methods.

Because of the advent of a new influenza A H1N1 strain, many countries have begun mass immunisation programmes. Awareness of the background rates of possible adverse events will be a crucial part of assessment of possible vaccine safety concerns and will help to separate legitimate safety concerns from events that are temporally associated with but not caused by vaccination. We identified background rates of selected medical events for several countries. Rates of disease events varied by age, sex, method of ascertainment, and geography. Highly visible health conditions, such as Guillain-Barré syndrome, spontaneous abortion, or even death, will occur in coincident temporal association with novel influenza vaccination. On the basis of the reviewed data, if a cohort of 10 million individuals was vaccinated in the UK, 21·5 cases of Guillain-Barré syndrome and 5·75 cases of sudden death would be expected to occur within 6 weeks of vaccination as coincident background cases. In female vaccinees in the USA, 86·3 cases of optic neuritis per 10 million population would be expected within 6 weeks of vaccination. 397 per 1 million vaccinated pregnant women would be predicted to have a spontaneous abortion within 1 day of vaccination.

WHAT'S KNOWN ON THIS SUBJECT: Studies on vaccine safety are crucial to the ongoing success of our national immunization program. ITP has a known association with MMR in young children, occurring in 1 in 40 000 doses. The risk after other childhood vaccines is unknown. WHAT THIS STUDY ADDS:This study found no increased risk of ITP after vaccines other than MMR in young children, confirmed an association of ITP with MMR, and also found that ITP may occur after certain other vaccines in older children.abstract BACKGROUND: The risk of immune thrombocytopenic purpura (ITP) after childhood vaccines other than measles-mumps-rubella vaccine (MMR) is unknown. METHODS:Using data from 5 managed care organizations for 2000 to 2009, we identified a cohort of 1.8 million children ages 6 weeks to 17 years. Potential ITP cases were identified by using diagnostic codes and platelet counts. All cases were verified by chart review. Incidence rate ratios were calculated comparing the risk of ITP in risk (1 to 42 days after vaccination) and control periods.RESULTS: There were 197 chart-confirmed ITP cases out of 1.8 million children in the cohort. There was no elevated risk of ITP after any vaccine in early childhood other than MMR in the 12-to 19-month age group. There was a significantly elevated risk of ITP after hepatitis A vaccine at 7 to 17 years of age, and for varicella vaccine and tetanus-diphtheria-acellular pertussis vaccine at 11 to 17 years of age. For hepatitis A, varicella, and tetanus-diphtheria-acellular pertussis vaccines, elevated risks were based on one to two vaccine-exposed cases. Most cases were acute and mild with no long-term sequelae.CONCLUSIONS: ITP is unlikely after early childhood vaccines other than MMR. Because of the small number of exposed cases and potential confounding, the possible association of ITP with hepatitis A, varicella, and tetanus-diphtheria-acellular pertussis vaccines in older children requires further investigation. 2 Since then, the association of live attenuated measles-mumps-rubella (MMR) vaccine and ITP has been well established. [3][4][5][6][7][8][9][10][11] ITP is known to occur after many types of infections, including numerous vaccine-preventable diseases. [12][13][14][15][16][17][18] In approximately two-thirds of ITP cases, there is a history of a preceding infectious illness in the days to weeks before ITP onset. 19 A subset of these children will have an identifiable virus, such as Epstein-Barr virus, varicella zoster virus, influenza virus, or HIV. 16 Because vaccines are designed to induce an immune response that mimics natural infection to produce immunologic protection, it is theoretically possible that vaccines besides MMR could trigger ITP. In addition, there have been case reports of ITP after other childhood vaccines, including hepatitis B vaccine (HBV), diphtheria-tetanuspertussis vaccine (DTP), and hepatitis A vaccine (Hep A). [20][21][22][23][24][25] However, the risk of ITP after childhood vaccines other than MMR is currently unknown.Known rare severe complica...

SYNOPSISMultiple neuroprotective agents have shown benefit for the treatment of acute spinal cord injury (SCI) in animal studies. However, clinical trials have, thus far, been uniformly disappointing. This review explores reasons for discrepancies between promising animal studies and disappointing clinical trials and potential barriers to extrapolation of research results from animals to humans. The three major barriers disclosed are: differences in injury type between laboratory-induced SCI and clinical SCI, difficulties in interpreting functional outcome in animals, and inter-species and interstrain differences in pathophysiology of SCI. These barriers can impair the effectiveness of animal models of SCI to predict human outcomes. While some of these barriers can be overcome, others are inherent to the animal models.

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