New Delhi, June 24: The death of an 11-month-old child due to vaccine-derived polio in Beed district of Maharashtra could have occurred because of low immunity, the union health ministry said Monday.

Vaccine-derived polio virus (VDPV) is extremely rare, and detected in children with immunodeficiency or in populations with low levels of immunization, the health ministry said in a statement.

Shivprakash Mundada, the doctor who treated the child, said: "The death was caused not by polio, but post-viral encephalitis complications."

The polio virus causes complications like swelling in the brain.

"The child was afflicted by a rare strain called the VDPV2," Mundada told IANS from Beed, adding that the infant caught the virus because of his low immunity levels.

The victim, Rohit R. Shelke, was detected as "polio positive" around two weeks ago. He died late Saturday at the Maharashtra Institute of Medical Science and Research (MIMSR) in Latur.

The infant had been suffering from brain lesions. The main cause of his illness or death has been reported as infection in the brain.

VDPVs are different from wild polio viruses and India has not reported any case of polio due to a wild polio virus since January 2011.

A total of 741 children had been paralysed by the wild polio virus in 2009 in India, accounting for over half of the global polio cases. Against this backdrop, India's success in keeping children free from any wild polio virus for over two years is being globally acclaimed as a major public health achievement.

WHO removed India from the list of polio endemic countries in 2012 following one year without any case due to wild polio virus in the country. Having completed more than two years without the wild polio virus case, India has moved closer to a polio-free certification in early 2014.

"The most important strategy for prevention of emergence of VDPVs is achieving and maintaining high routine immunisation coverage with OPV doses among infants," Health Secretary Keshav Desiraju said.

Detection of VDPVs will not impact the polio eradication certification process. The pre-requisites for polio free certification of a region includes absence of wild polio virus in all countries of the region for three consecutive years, presence of certification-standard surveillance, and the completion of laboratory containment activities (which ensure that the virus is only used for scientific purposes, within the laboratory). (IANS)