There have been some media reports that polio virus (P2 strain) has resurfaced in India for the first time in 5 years. However, it is not true as detected polio virus strain is vaccine derived poliovirus (VDPV) in a sewage sample collected near the Secunderabad railway station. However, no children have been found to be affected by the detected VDPV isolate in the nearby areas. Last case of Wild Polio Virus Type 2 in country was reported 17 years back in 1999. The detection of vaccine derived polio virus (VPDV) does not change the polio free status. It only indicates the robustness of the surveillance system and willingness of the country to detect any kind of polio virus even from the environment (sewage). Vaccine derived polioviruses are rare strain of the polioviruses that have genetically mutated from the strain contained in the Oral Polio Vaccine (OPV)
A rapid surveillance review of the area revealed that the population immunity against polio type 2 is high as trivalent oral polio vaccine (tOPV) was in use in the state until 24th April, 2016 and two mass vaccination campaign were conducted in January and February, 2016. As per recent sample survey in the area, 94% children were found to have received at least 3 doses of OPV. Therefore, chances of its transmission in concerned area is unlikely.
However, as a precautionary measure against Polio, a special immunization drive is being held, covering high-risk areas of Hyderabad and Rangareddy districts, starting from 20th June, where an estimated 300,000 children will be protected against polio using Inactivated Polio Vaccine (IPV). The special immunisation campaign will ensure all vulnerable children living in high-risk areas are given protection against polio.
As part of the special campaign being organised now, children between the age group of six weeks to three years will be given an additional dose of the injectable polio vaccine (IPV). Vaccination booths will be set up in the areas being covered in these campaigns. However, there will be no door-to-door vaccination campaign. Parents of children living in these areas will be encouraged to ensure that their children get the IPV dose from the nearest vaccination booth which will provide additional protection against all types of polio.
The special campaign covering Hyderabad and Rangareddy districts is yet another evidence of India’s strong commitment to remain polio-free. The last case due to wild poliovirus in India was detected on 13 January 2011 and the country was certified polio-free by WHO in March 2014. The polio-free certification pertains to the absence of wild poliovirus and thus country remains polio-free.
India continues to maintain a highly sensitive surveillance system for polio. All cases of paralysis with sudden onset in children up to 15 years (which is called Acute Flaccid Paralysis or AFP) are picked up by the polio surveillance network. Each of these cases is followed up and their stool samples tested for poliovirus in WHO accredited laboratories. In addition, sewage samples are collected from over 30 sites spread across the country for poliovirus detection at regular intervals.
Between Jan 2015 and May 2016, a total of 14 sewage samples collected from different parts of the country tested positive for VDPVs. All of these have been responded to urgently and appropriately with polio vaccination campaigns. None of these VDPVs detected in the sewage infected any children, so far.
The response by the health authorities to the VDPV in Hyderabad is in accordance with World Health Organization protocols to mitigate any risk of spreading of the virus. WHO, UNICEF and Rotary are supporting Ministry of Health and Family Welfare in rolling out the polio campaign.
Strong measures have been put in place in India to mitigate the risk of an importation and spread of poliovirus from countries with continued circulation of poliovirus. Country has done two nationwide polio campaigns this year. Polio vaccination is being carried out at international borders and is a must for people travelling to polio affected countries.
The polio eradication programme in India continues to protect children from the crippling disease by conducting two nationwide mass polio vaccination campaigns and two to three sub-national campaigns each year. Intensive efforts are also being undertaken in India to improve routine immunization coverage that involves administering polio vaccines, in addition to other vaccines, to infants under the Universal Immunization Programme (UIP).