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Immunization in India with trivalent and monovalent oral poliovirus vaccines of enhanced potency
Insights
This study investigated enhanced oral poliovirus vaccine (OPV) for infants in warm climates. A 10-fold higher virus dose showed modest improvements, indicating partial success in overcoming infant immune refractoriness to OPV.
Area of Science:
- Pediatrics
- Immunology
- Vaccinology
Background:
- Infants in warm climates often exhibit a reduced serological response to oral poliovirus vaccine (OPV).
- This diminished response can compromise vaccine efficacy and disease prevention in vulnerable populations.
Purpose of the Study:
- To enhance the serological response of infants to oral poliovirus vaccine (OPV) in warm climates.
- To evaluate the effectiveness of an enhanced-potency OPV with a 10-fold higher virus dose.
Main Methods:
- Administered trivalent and monovalent OPV with 10x standard virus dose to 79 infants (6-41 weeks old).
- Assessed seroconversion rates for poliovirus types 1, 2, and 3 post-vaccination.
Main Results:
- Single dose of enhanced trivalent OPV yielded seroconversion rates of 42% (type 1), 85% (type 2), and 31% (type 3).
- Single dose of enhanced monovalent OPV showed higher rates: 89% (type 1), 93% (type 2), and 76% (type 3).
- Enhanced OPV provided only slight improvements over standard OPV after one dose but approached efficacy of multiple standard doses.
Conclusions:
- Enhancing the virus inoculum 10-fold partially overcame host immune refractoriness in infants.
- Further optimization is needed to achieve robust serological responses comparable to multiple standard OPV doses.
Abstract:
In an attempt to improve the serological response of infants in warm climates to oral poliovirus vaccine (OPV), the authors administered to 79 children between 6 and 41 weeks of age trivalent and monovalent OPV containing a virus dose 10 times as high as that found in the standard vaccine. The seroconversion rates following one dose of this trivalent OPV were 42% to type 1 poliovirus, 85% to type 2, and 31% to type 3. These rates are only slightly better than those previously reported after one dose of standard trivalent OPV and much lower than those achieved after 3 doses. The seroconversion rates following one dose of the monovalent OPV of enhanced potency were 89%, 93%, and 76%, respectively. These rates are comparable to those achieved after 5 doses of the standard trivalent OPV. Thus the refractoriness of host response was only partly overcome by enhancing the virus inoculum 10-fold.