The Telangana government on Tuesday sounded an emergency after an active P2 strain of polio virus (vaccine-derived) was detected in a sample of water collected from a drain in Hyderabad's Amberpet area.
The state government has now airlifted two lakh vaccines from Geneva to vaccinate more than three lakh children in Hyderabad and Ranga Reddy district as a "preventive measure".
We spoke to Dr G Srinivasa Rao, chief programme officer, National Health Mission, Telangana about the detection of the strain, and he has provided us with some answers.
Where did this virus come from?
We cannot know that for sure, but the assumption is that it is from a child in Hyderabad with weak immunity and has had a polio vaccine in the past 10 months. The virus could have made its way to the drain with the child’s stool. But the child could very well be from outside Hyderabad as well.
Is the government trying to trace this child?
They will try, but it is a very difficult task. Dr Rao explains why.
“The nala from which the strain was found spreads across one-thirds of Hyderabad city, so we cannot look for one child among the several lakhs there now. There are a couple of railway stations in that area, so the sample could be from one of the trains, which could be a local or an inter-state train,” he says.
Also, the top priority right now is to vaccinate the children in the target areas.
What is the next plan of action?
A massive vaccination drive. Children in Hyderabad will be vaccinated between June 21 and June 26. The entire process has to be completed within 2-3 weeks of the date of detection of the virus, so the government is already on the job. Vaccines have been airlifted from Geneva.
Who are the target children?
All children in the target areas in the age group 6 weeks to 3 years will be getting the vaccination. This adds up to an estimated 3 lakh people.
All areas in Hyderabad around the nala and all the high-risk areas in Hyderabad and Ranga Reddy district are the target areas. “Almost the whole of Hyderabad will be covered,” says Dr Rao.
What should parents do?
“Parents should first get the vaccination done, that is the only solution to this,” says Dr. Rao
But he adds, “If there are any polio-like symptoms which are noticed by parents, then they can take the kids to the public health centres. But we don’t think there is a risk of that. This kind of a situation does not arise since we would have already known about this. Our surveillance system is very strong.”
How serious is the Hyderabad discovery?
There is no need to panic, but it is serious enough to warrant a massive, precautionary vaccination drive.
India has been polio free for several years now, and while a direct case of polio has not been reported yet, the latest polio strain is the latest among many cases of Vaccine Derived Polio Virus (VDPV) strains, two of which were reported in 2014.
“Our immunization level is 90-95%, which is why there is no need to panic immediately,” says Dr Rao, and adds, “Also this is a Vaccine Derived Polio Virus (VDPV) which is not as dangerous, so this is just a precautionary measure there is no need to panic.”
What is Vaccine Derived Polio Virus (VDPV)
The oral polio vaccine (OPV) is not unlike any other vaccine, and consists of small amount of the weakened virus, which stays in the intestine for a small period and helps the body develop immunity by building anti-bodies against the virus.
Following this, the vaccine-virus is excreted from the body.
The WHO states:
On rare occasions, if a population is seriously under-immunized, an excreted vaccine-virus can continue to circulate for an extended period of time. The longer it is allowed to survive, the more genetic changes it undergoes. In very rare instances, the vaccine-virus can genetically change into a form that can paralyse – this is what is known as a circulating vaccine-derived polio virus (VDPV).
However, the detection of a VDPV is still said to be a rare case.
If India is polio-free, why is this happening?
As explained above, this is a vaccine derived virus which was always expected. Read more about why we should not be complacent here.
“This is not the first time it is happening, and won’t be the last. We have to be prepared,” says Dr. Rao.
“It is because of the surveillance systems that we have been able to detect it early. This was detected because of our environmental surveillance system – we take samples from the environment to test.”
“Bangladesh and Pakistan still have not eradicated polio, so India might get cases from there,” says Dr. Rao, and adds, “In Hyderabad, people especially in the Old City are in regular contact with people in Middle-East and Pakistan, that’s why we have to be careful.”