Sabin-related poliovirus vaccine strains isolated from transverse myelitis cases in Brazil

Rare adverse events associated with oral poliovirus vaccine in Brazil

“…Molecular characterization studies of poliovirus strains isolated in Brazil from rare paralytic poliomyelitis cases and also from cases classified as Guillain-Barré syndrome, transverse myelitis and facial paralysis demonstrated that the isolates are derived from the Sabin vaccine strains (77)(78)(79)(84)(85)(86)(87)(92)(93)(94), and that most of the isolates analyzed present genomic modifications known or suspected to increase neurovirulence (78,79,84,85,87,92). The temporal association between the isolation of these strains and the Guillain-Barré syndrome, transverse myelitis and facial paralysis in Brazil suggested that these diseases could also be triggered in rare cases by Sabin poliovirus vaccine strains.…”

“…Several lines of evidence have suggested that polioviruses and other enteroviruses might cause a persistent infection in humans and chronic diseases of the central nervous system (101)(102)(103)(104)(105). The isolation of polioviruses derived from the Sabin vaccine strains from patients presenting paralysis after the onset of motor deficiency and in which the last vaccine dose was given months or years before the onset of disease (84,85,(92)(93)(94) suggested transmission or a persistent infection. Although most poliovirus infections are silent (106), there is always the possibility of transmission of Sabin vaccine-derived strains to other individuals that may occasionally develop the disease (84).…”

“…Interestingly, several poliovirus strains were isolated (77) from fecal samples of paralysis cases in Brazil classified as Guillain-Barré syndrome (91) and transverse myelitis. Polioviruses isolated from these cases were characterized as related to the Sabin vaccine strains by molecular hybridization and PCR (77,85,(92)(93)(94). Partial sequencing of the genome of some of these strains confirmed the vaccine origin and also demonstrated mutations known to increase neurovirulence (85,92).…”

“…Partial sequencing of the genome of some of these strains confirmed the vaccine origin and also demonstrated mutations known to increase neurovirulence (85,92). Analysis of the epidemiological data for these cases demonstrated that in most of them the last Sabin vaccine dose was given months or years before the onset of the disease and the isolation of the polioviruses (85,(92)(93)(94). The temporal association between the isolation of these strains from fecal samples and the Guillain-Barré syndrome or transverse myelitis in Brazil suggested that the Sabin vaccine-derived poliovirus strains could also rarely trigger these diseases.…”