With polio eradication appearing to be a distant dream in Uttar Pradesh, the State Health Directorate has decided to revert to its earlier 'polio immunisation strategy'. Instead of the monovalent polio vaccine, targetting P1 type polio virus, the 'policy makers' have decided to use trivalent vaccine in the next phase of pulse polio drive starting from April 8.
The objective is to target all the three types of wild polio virus (P1, P2 and P3), which have been recently found in children suffering from polio attack in the high endemic areas, including Allahabad, Moradabad and Rampur.
Notably, in the past the trivalent vaccine was used to immunise children during the pulse polio drive. But as the number of polio cases came down significantly in the year 2004-05, the government decided to switch over to monovalent vaccine to enhance the impact of eradication activities in the high endemic areas. Moreover, the monovalent vaccine was very effective in areas where only wild polio virus type-1 was circulating.
"The government has probably decided to switch over to trivalent vaccine instead of the monovalent vaccine, which was being used since the last six-seven rounds, after the fresh cases of polio, having P2 and P3 wild polio virus strains, started reporting from different parts of UP, including Allahabad," said Dr Shantimal Singhavi, Chief Medical Officer.
Dr Singhavi said the monovalent vaccine offered certain advantages in areas where wild polio virus P1 was still circulating. The vaccine increased the immunity of children against P1 type polio virus as compared to the trivalent vaccine, he added.
District Immunisation Officer Dr Swatantra Mishra said an important advantage of monovalent vaccine was that it produced a much stronger response than trivalent vaccine, in children immunised for the first time, including very young babies. Since, most of the cases of polio were found in children below two years of age, this vaccine was very effective on them. However, the government possibly decided to change its polio eradication strategy, after new strains of P2 and P3 virus were found in children in different parts of UP. These two strains were earlier thought to have been eradicated, he added.