The biggest threat is that in a vaccine-derived polio virus (VDPV), the source of the virus is the vaccine itself. We have listed things that we all should know, since, after all, it is about the futures and lives of our children.
Post study, Telangana government, as part of preventive action on Tuesday, called for a special polio immunisation drive in Hyderabad after a surveillance study conducted by the World Health Organisation (WHO) found traces of vaccine-derived polio virus in the city’s Amberpet nala, a major sewage canal in the city.
You should definitely know the below listed points about vaccine-derived polio virus (VDPV) and the concerns around it.
Polio:
Poliomyelitis or polio is a highly infectious disease that invades the nervous system, and causes paralysis. It is a transmittable disease [from person to person], mainly through the faecal-oral route, affecting children under five years of age. India was declared a polio-free country in March 2014, after years of relentless vaccination.
Hyderabad study findings:
WHO conducts surveillance for maintenance of polio eradication in polio-free countries where it collects samples of sewage water to find any traces of polio viruses. In one such study in Hyderabad in April, out of 30 samples collected, one sample from Amberpet nala contained traces of type-2 VDPV. The Lab tests found that the virus passed through human body has undergone mutation or nucleotide change. A similar virus strain was detected in Delhi, Bihar and Gujarat too.
Vaccine-derived polio virus:
In VDPV, the source of the virus is the vaccine itself. Oral polio vaccine, popularly called as polio drops, contain a live, attenuated or weakened polio virus. As a child is vaccinated, the weakened vaccine-virus replicates in the intestine and enters into the bloodstream, triggering a protective immune response in the child. Like wild poliovirus, the child excretes the vaccine-virus for a period of six to eight weeks.
VDPV a matter of concern:
Though cases of paralysis due to VDPV are rare as the virus has to circulate for a long time in the community of under-immunised population before it can infect and cause paralysis in someone. The main issue is that India reports a high number of non-polio—AFP or paralytic—cases in children who are less than 15 years of age, which the study links to the VDPV. WHO reports suggest that more than 50,000 AFP cases are investigated in India every year as a part of its surveillance system.
OPV vs IPV
The detection of VDPV has intensified the already felt need of replacing oral polio vaccine (OPV) with inactivated polio vaccine (IPV). IPV is given through an injection that contains inactivated virus and is considered to be safer than OPV that contains live virus. WHO is already advocating IPV over OPV as part of its global endgame strategy on polio eradication. India has introduced IPV in the mandatory immunization programme in six states and currently is given in addition to the existing OPV.
The article first published on www.lafdatv.com
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