How to predict the immune status of poliovirus vaccinees? A comparison of virus neutralization at a very low serum dilution versus ELISA in a cohort of infants

Simhon A (Unit of Clinical Virology, Department of Clinical Microbiology, Hadassah University Hospital, Jerusalem, Israel), Lifshitz A, Abed Y, Lasch EE, Schoub Band Morag A. How to predict the immune status of poliovirus vaccinees? A comparison of virus neutralization at a very low serum dilution versus ELISA in a cohort of infants. International Journal of Epidemiology, 1990, 19: 164-168.A cohort of children from Gaza was observed from birth to the age of one year. Blood specimens were collected at birth, before and after poliovirus vaccination and at one year of age. Poliovirus immunity before and after vaccination was assessed by ELISA and virus neutralization (NT). Positive predictive values for ELISA were between 81.5% and 90.8%. However, ELISA revealed a high frequency of false negatives, and unacceptably low negative predictive values between 28.6% and 55.4%.The history of poliovirus immunity in the cohort was further investigated by NT. A high level of seropositivity to poliovirus type 1 (PV-1) was found. In cord blood, 83.3% had a NT titre ≥4 and 99.0% had a titre ≥2. Similarly, by one year of age, 85.7% had a titre ≥4 and 90.5% had a titre ≥2. Seropositivity to PV-2 and PV-3 were slightly lower, ie 80.8% of children had a PV-2 titre ≥4and 75.4% had a PV-3 titre ≥4. As for other developing areas, poliomyelitis eradication in Gaza will come about when universal vaccination fills all 'immunity gaps' and improved sanitation and housing reduces the endemicity of wild polioviruses.