Key result
Surveillance of 616 healthy children in Madagascar identified 3 potentially pathogenic type 2 vaccine-derived polioviruses, indicating reemergence of the virus due to insufficient vaccine coverage.
Low oral polio vaccine coverage enables the reemergence of neurovirulent vaccine-derived polioviruses in healthy children, while overcrowding in refugee camps facilitates severe Hepatitis E outbreaks with high maternal mortality.
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Low vaccine coverage may enable VDPV reemergence; leaves open optimal surveillance and catch-up strategies in similar settings.
To the Editor: Poliomyelitis outbreaks caused by pathogenic vaccine-derived polioviruses (VDPVs) are primarily a result of low polio vaccine coverage. Low coverage enables interhuman circulation of polioviruses (PVs) from the oral polio vaccine (OPV), and it enables genetic drift of the viruses and their subsequent reversion to neurovirulent phenotypes (1). Polio outbreaks associated with type 2 or 3 VDPVs (VDPV2s or VDPV3s) were reported in 2001-2002 and 2005 in Toliara Province in southern Madagascar (2,3). These VDPVs were found in patients with acute flaccid paralysis (AFP) and in healthy children who were contacts of the patients with AFP (2,4). The genomes of these VDPVs belong to several independent, complex mosaic recombinant lineages composed of sequences derived from vaccine polioviruses and other co-circulating species C human enteroviruses (human EV-C) (4,5). The 2001The -2002
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Razafindratsimandresy et al. (2013) conducted a letter in Vaccine-derived poliovirus (n=616). Low oral polio vaccine coverage was evaluated on Detection of vaccine-derived polioviruses (VDPVs). Surveillance of 616 healthy children in Madagascar identified 3 potentially pathogenic type 2 vaccine-derived polioviruses, indicating reemergence of the virus due to insufficient vaccine coverage.
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