Poliovirus neutralising antibody in infants and cord blood.

Singapore participated in the WHO EPI protocol for rapid assessment of serological response to three doses of standard oral poliovirus vaccine. The 100% seropositive finding of thirty infants below one year old is no proof of seroconversion rate to the Trivalent Oral Poliovirus Vaccine (TOPV) administered. Investigation of 100 cord blood samples showed that passively transferred maternal poliovirus neutralising antibody cannot be relied upon for protection of infants against poliomyelitis. This paper emphasises the importance of vaccine potency testing and serves as a timely reminder that although the last case of indigenous poliomyelitis was recorded in 1974, non Sabin-like (wild) polioviruses are being isolated from imported cases and foreigners hospitalised in Singapore, and unexpectedly, from the conjunctiva and pharynx of Singaporeans treated for conjunctivitis. It discusses the WHO (World Health Organization) Plan of Action for Eradication of Polio in the Western Pacific Region which includes Singapore.