One-year decline of poliovirus antibodies following fractional-dose inactivated poliovirus vaccine

Document Type



Paediatrics and Child Health; Women and Child Health


Background: Fractional dose (1/5th of full intramuscular dose) of inactivated poliovirus-vaccine administered intradermally (fIPV) is used as IPV dose-sparing strategy. We compared the rate of decline of poliovirus antibodies (PVA) in recipients of either two doses of fIPV or IPV.
Methods: Community-based randomized controlled trial was conducted in Karachi, Pakistan. Children aged 14 weeks were randomized into fIPV or full IPV study arms (A, B) and received one vaccine doses at 14 weeks and one at 9 months of age. PVA were measured at 14, 18 weeks and 10, 21 months of age.
Results: Seroprevalence of poliovirus-type 2 antibodies of 170/250 (68%) enrolled children after two IPV or fIPV doses at 10 months of age in arms-A and B reached 100% vs 99% (p=0.339); and at 21 months it was 86% vs 67% (p=0.004). Between 10 and 21 months of age, the antibody-titers in log2 scale dropped from >=10.5 to 6.8 in arm-A; and from 9.2 to 3.7 in arm B.
Interpretation: A significant decline in antibody titers12 months following second IPV dose. The slope of decline is similar for both full IPV and fIPV recipients. The results provide further evidence that fIPV is a viable option for IPV dose-sparing.


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Publication (Name of Journal)

The Journal of Infectious Disease