Vaccine
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While a number of studies remain to be completed, evidence is mounting that there is no demonstrable risk for infants immunized with vaccines containing thiomersal. Epidemiological studies in the US have shown no developmental or other central nervous system abnormalities resulting from exposure to vaccines containing thiomersal. During the initial evaluation of thiomersal in vaccines during 1999, the toxicological profile of ethyl mercury was unknown and presumed to be the same as that of methyl mercury. ⋯ Until such time as the scientific evidence is to hand, thiomersal-free presentations of hepatitis B are to be preferred for the birth dose. Given the same levels of exposure, adults are at much lower levels of risk because of increased body mass. It is not possible to prove that thiomersal is completely safe-epidemiology can only quantify a risk, not prove its absence.
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The only US FDA licensed smallpox vaccine, Dryvax, was associated with rare but serious neurological adverse events. After smallpox was eradicated in the United States, mass vaccination ceased in 1971. As counter-bioterrorism/biowarfare measures, new smallpox vaccines are now being investigated. ⋯ Expression of virus antigen in neural cells and infectious virus replication in the brain was also significantly different between the two strains. In addition, the appearance of high titer virus antibody correlated with the clearance of virus from brain. With further validation, this assay incorporating a licensed vaccine reference standard and positive control strain may provide important pre-clinical neurotoxicity data on new vaccinia-based smallpox vaccine strains.
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A mass vaccination was carried out in the state of Minas Gerais, Southeast region of Brazil, to control an outbreak of sylvatic yellow fever in 2001. During the outbreak the surveillance system identified two fatal cases temporally associated with YF vaccination. ⋯ Partial nucleotide sequence of parts of prM/E and the non-structural (NS) 5 genes and 3' non-coding region (3' NCR) was employed to characterize the origin of yellow fever virus (YFV) involved in both cases. Wild-type YFV was identified as the etiologic agent responsible for the disease.
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Previous studies have suggested that providers of alternative medicine may harbour anti-vaccination attitudes and that these attitudes may develop at an early stage in their careers. We further explored this question by conducting a survey to determine the attitudes of students of naturopathic medicine, a growing alternative medicine discipline, towards recommended paediatric vaccines. ⋯ Importantly, both willingness to advise full vaccination and trust in public health and conventional medicine decreased in students in the later years of the programme. Our findings suggest that public health and conventional medical supporters of vaccination need to identify mechanisms for engaging in discussion with this population of complementary/alternative medical professionals at an early stage in their careers.
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Media attention and consequent public concerns about vaccine safety followed publication of a small case-series of children who developed autism after receipt of the measles-mumps-rubella (MMR) vaccine. Many well-controlled studies performed subsequently found no evidence that MMR vaccine causes autism. However, despite these studies, some parents remain concerned that the MMR vaccine is not safe. We will discuss the origins of the hypothesis that the MMR vaccine causes autism, studies performed to test the hypothesis, how these studies have been communicated to the public, and some suggested strategies for how this communication can be improved.