Vaccine
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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.