Key result
Three consecutive lots of Sabin-strain IPV demonstrated immunological equivalence (GMT ratios 0.67-1.50) and the pooled sIPV was non-inferior to control IPV for seroconversion of types 1, 2, and 3.
Why the study?
Sabin-strain-based inactivated poliovirus vaccine plays an important role in poliomyelitis eradication, but its safety, immunogenicity, and lot-to-lot consistency required evaluation in 2-month-old infants.
Does Sabin-strain inactivated poliovirus vaccine provide consistent immunogenicity and non-inferior seroconversion compared to control IPV in healthy 2-month-old infants?
RCT (n=1,300)
Double-blind
1:1:1:1 ratio
Does Sabin-strain inactivated poliovirus vaccine provide consistent immunogenicity and non-inferior seroconversion compared to control IPV in healthy 2-month-old infants?
Three consecutive lots of sIPV demonstrated robust, consistent immunogenicity and acceptable safety comparable to control IPV in 2-month-old infants.
Answers are grounded in this paper and cite their sources.
Supports sIPV as an alternative in infant polio schedules; confirms lot-consistent non-inferior immunogenicity versus standard IPV in RCT.
BACKGROUND: The Sabin-strain-based inactivated poliovirus vaccine (sIPV) plays an important role in poliomyelitis eradication in developing countries. As part of the phase III clinical development program, this study aimed to evaluate the safety, immunogenicity and lot-to-lot consistency of the sIPV in 2-month-old infants. METHOD: We conducted a phase III, randomized, double-blind, positive-controlled trial in which 1300 healthy infants were randomly assigned to four groups in a 1:1:1:1 ratio to receive one of the three lots of the sIPV or the control IPV at 2, 3 and 4 months of age. Serum samples were collected before the first dose and 30 days after the third dose of vaccination to assess the immunogenicity. Solicited local and systemic reactions were recorded within 7 days and unsolicited adverse events within 30 days after each vaccination. RESULTS: Of the 1300 randomized infants, 1190 infants completed the study and were included in the per-protocol population. The seroconversion rates in the three lots of the sIPV were 95.67%, 97.03% and 95.59%, respectively, for type 1; 94.33%, 93.73% and 92.88%, respectively, for type 2; and 98.67%, 99.67% and 99.32%, respectively, for type 3. The ratios of GMTs for poliovirus types 1, 2 and 3 of each pair of lots were all between 0.67 and 1.50, therefore meeting the predefined immunological equivalence criteria. For the seroconversion rate of poliovirus types 1, 2 and 3, the pooled sIPV group was non-inferior to the IPV group. The incidence of solicited and unsolicited adverse reactions (ARs) was similar in the pooled sIPV lots and the IPV group, and most of them were mild to moderate in severity. Non-vaccine-related serious adverse events (SAEs) were reported. CONCLUSIONS: Three consecutive lots of sIPV demonstrated robust and consistent immunogenicity. The safety and tolerability of the sIPV was acceptable and similar to that of the IPV.
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Zheng et al. (2022) conducted an RCT in Healthy infants (n=1,300). Sabin-strain inactivated poliovirus vaccine (sIPV) vs. Control IPV was evaluated on Seroconversion rates for poliovirus types 1, 2, and 3. Three consecutive lots of Sabin-strain IPV demonstrated immunological equivalence (GMT ratios 0.67-1.50) and the pooled sIPV was non-inferior to control IPV for seroconversion of types 1, 2, and 3.
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