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Efficacy of inactivated poliovirus vaccine in India
Insights
Inactivated poliovirus vaccine (IPV) showed satisfactory immunogenic efficacy in Indian infants, with high seroconversion rates. An 8-week interval between doses and absence of maternal antibodies improved vaccine response.
Area of Science:
- Immunology
- Vaccinology
- Pediatrics
Background:
- Oral poliovirus vaccine (OPV) has shown high rates of vaccine failure in India.
- Inactivated poliovirus vaccine (IPV) is an alternative immunization strategy.
- Evaluating IPV immunogenicity in infants is crucial for public health.
Purpose of the Study:
- To assess the immunogenic efficacy of inactivated poliovirus vaccine (IPV) in Indian infants.
- To determine the impact of child's age, maternal antibody presence, and dose interval on antibody response.
- To compare IPV efficacy against poliovirus types 1, 2, and 3.
Main Methods:
- A total of 150 infants (6-45 weeks old) received 3 doses of IPV.
- Vaccine doses were administered at 4- or 8-week intervals.
- Antibody responses were measured to assess seroconversion rates and titres.
Main Results:
- Overall seroconversion rates were 99% (type 1), 89% (type 2), and 91% (type 3).
- Higher seroconversion rates for types 2 and 3, and antibody titres for types 1 and 2, were observed with 8-week intervals and absence of maternal antibodies.
- Infants without maternal antibodies receiving IPV at 8-week intervals achieved 100% (type 1), 100% (type 2), and 96.2% (type 3) seroconversion.
Conclusions:
- Inactivated poliovirus vaccine (IPV) demonstrates satisfactory immunogenic efficacy in Indian infants.
- Optimizing the vaccination schedule (8-week intervals) and considering maternal antibody status can enhance IPV effectiveness.
- IPV is a viable option for poliovirus prevention in regions with high OPV failure rates.
Abstract:
The immunogenic efficacy of inactivated (Salk) poliovirus vaccine (IPV) was evaluated in infants in India, in view of the high frequency of vaccine failure after immunization with oral (Sabin) poliovirus vaccine (OPV). A total of 150 infants, aged 6-45 weeks, were given 3 doses of IPV, with intervals of 4 or 8 weeks between doses. The effect on the antibody response of child's age, presence of maternal antibody before immunization, and interval between doses was assessed. The overall seroconversion rates to poliovirus types 1, 2, and 3 were 99%, 89%, and 91%, respectively. Seroconversion rates to types 2 and 3, and antibody titres to types 1 and 2, were higher (i) in infants given vaccine doses at 8-week intervals and (ii) in those without detectable maternal antibody. The seroconversion rates in infants without maternal antibody, who were given IPV at 8-week intervals, were 100%, 100%, and 96.2% to poliovirus types 1, 2, and 3, respectively. Thus the immunogenic efficacy of IPV was found to be satisfactory.