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| Oral Polio Vaccination, Credit:WikiPedia |
Vaccine Derived Polio Virus (VDPV) is special case of and is completely different from the Wild poliovirus. The Oral Polio Vaccine (OPV) contains attenuated vaccine virus. It enters the intestine where it replicates itself. When this enters the bloodstream, our body becomes alert of the alien substance and the immune system starts responding against the virus. However when the children who was given ORV is immunodeficiency, the virus could mutate genetically altering from its original attenuated virus as vaccine-virus. Now this virus is called the vaccine-derived poliovirus.
The problem may get aggravated due to the fact that the children who are given ORV, usually excrete the virus for about 6 to 8 weeks. Thus, if a community is seriously immune deficient and anyone of their children has VDPV, there are higher chances that it may get passed on to others. In very rare cases (1 in 2.7 million cases), this VDPV can cause paralysis as the original wild poliovirus does.
Vaccine Derived Polio Virus can be classified into three type:
- circulating vaccine-derived poliovirus (cVDPV)
- immunodeficiency-related vaccine-derived poliovirus (iVDPV)
- ambiguous vaccine-derived poliovirus (aVDPV)
India. having been successful in eliminating wild poliovirus. The last wild poliovirus case in India was registered in 2011 (India had 741 polio cases in 2009!). Since then not even a single polio case has come up and for this effort, World Health Organisation (WHO) removed India from the list of countries endemic to poliovirus in 2012 following a year without any polio cases. And India is now getting closer to a polio-free certification from WHO in early 2014.
The GOI has made sure that the occurrence of VDPV has no effect on the country's chances for getting the polio-free certificate as the VDPV is completely different from the wild poliovirus.The recent death of 11-month old boy in Maharashtra has once again brought forth the need to find and treat immunodeficiency people.
Govt Measures:
Circulating VDPV to a certain extant can cause the virus to spread among community and very rarely can affect people with immunodeficiency. Hence the GOI is serious about addressing the issue of immunodeficiency through various measures. It is in this context that the government declared 2012-13 as ‘Year of Intensification of Routine Immunisation’. The objective is to attain higher routine immunisation rates and protect children from all vaccine preventable diseases.
Govt is conducting ‘Special Immunisation Weeks’ in 2013 in the 411,129 high risk areas identified by the Polio eradication programme covering areas of slums, nomadic sites, construction sites, brick kilns and other areas housing people on the move, who often miss out on immunisation due to their transient nature.
Sources:
WHO
PIB
Polioeradication.org
Very useful
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