Maintenance of high levels of immunity to poliomyelitis is priority in India as transmission of wild polioviruses in its two states has never been interrupted. Determination of serological profile of vaccines in disease endemic as well as disease free areas is important for evaluation of efficacy to the extended polio vaccination program in the country. A hospital based study to determine antibody levels against three poliovirus serotypes in selected children was performed in Pune city which has been disease free since, last 11 years. Levels of neutralizing antibodies against poliovirus types 1, 2 and 3 in the sera of group of 90 children below 2 years of age and have participated in Pulse Polio Immunization (PPI), were determined. The geometric mean antibody titers were 1:811, 1:659 and 1:226 for poliovirus types 1, 2 and 3, respectively. Significantly high antibody titers for poliovirus types 1 and 2 were found after 6 polio doses. However, about three to five fold decrease in the antibody titers for poliovirus type 3 was noted. About 17.7% of serum samples showed poliovirus type 3 antibody titer less than 1:52. In view of the current type 3 epidemic in India, the study suggest that perhaps, single round of PPI and a booster of monovalent type 3 following routine immunization schedule may be required to create adequate immunity in children in a disease free area such as Pune. Targeting of all the children below 5 years of age for each PPI may not be necessary. This study also suggests that protective antibody titer in India should be redefined.
A.S. Moghe, S.G. Gangal, S.H. Palkar and S.N. Jaiswal, 2010. Antibody Response of Children Receiving Multiple Doses of Oral Polio Vaccine in Disease Free Area of India. Asian Journal of Epidemiology, 3: 75-83.