Paralytic poliomyelitis associated with the Sabin 3 revertant strain of poliovirus in Bahrain

We report a case of vaccine-associated paralytic poliomyelitis (VAPP) in Ba hrain. The case occurred in an 8-week-old infant who had received a dose of oral polio vaccine (OPV) 7 days after birth. She was in contact with two v accinees who had received OPV during the national immunisation campaign con ducted 10 days before her birth. Specimens from the infant were sent to the WHO Collaborating Centre for Virus Reference and Research Laboratory for s erological testing and virus detection, including genomic sequencing. Clini cal and virological features are presented of a case of VAPP caused by the Sabin 3 strain of poliovirus that had reverted towards neurovirulence. The case represents one in 51,879 first doses of OPV distributed between 1995 a nd 1998. In order to reduce further the risk of VAPP, the dose of OPV at bi rth has been discontinued and a sequential schedule of inactivated polio va ccine (IP-V) followed by OPV will be recommended.