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Polio Threat Resurges in India: Variant Strains Cause Paralysis

  //health-fitness.news-articles.net/content/2026/ .. es-in-india-variant-strains-cause-paralysis.html
  Published in Health and Fitness on Sunday, February 15th 2026 at 21:39 GMT by ThePrint
      Locales: India, Uttar Pradesh, Maharashtra, INDIA

New Delhi, February 16th, 2026 - While India was officially declared polio-free in 2014, a persistent and evolving threat remains: variant poliovirus strains. These genetically distinct viruses are causing paralysis in under-immunised children, prompting renewed concerns and a call for strengthened public health strategies. The re-emergence of these strains highlights the complexities of maintaining a polio-free status even after eradication of the wild poliovirus.

Speaking to ThePrint, Dr. Chandrakant Pandav, a respected public health expert and former advisor to the Union health ministry, explained the nuanced situation. "We successfully eradicated the wild poliovirus, a monumental achievement. However, these are different strains, and critically, they are causing paralysis in children who haven't received full immunisation. This underlines the ongoing need for vigilance and comprehensive vaccination programs."

Understanding Variant Poliovirus Strains

These variant strains aren't simply remnants of the original virus; they are mutations that occur as the poliovirus circulates within communities. The virus, like all viruses, evolves. These mutations can lead to strains that are better at evading the immunity conferred by previous vaccinations or natural infection. Currently, the two primary types of variant poliovirus causing concern are Vaccine-Derived Poliovirus (VDPV) and Immunodeficiency-Associated Poliovirus (IAPV).

VDPV arises specifically in areas where vaccination coverage is suboptimal. The oral polio vaccine (OPV), while highly effective, uses a weakened (attenuated) form of the poliovirus. In populations with low immunity, this weakened virus can, over time, mutate and regain its ability to cause paralysis. Essentially, the very vaccine designed to protect can, in rare instances, contribute to the spread of a paralysing variant. This phenomenon is well-understood, and is why global efforts are increasingly focused on switching to inactivated polio vaccine (IPV) where feasible.

IAPV, on the other hand, emerges in individuals with severely compromised immune systems - often due to conditions like HIV/AIDS or certain genetic disorders - after they receive the OPV. In these individuals, the weakened virus can persist and mutate within their bodies for extended periods, potentially shedding into the environment and infecting others.

The Continuing Threat & Resurgence Factors

Though generally weaker than the wild poliovirus, VDPV and IAPV are still capable of causing paralysis, particularly in unvaccinated or under-vaccinated children. Crucially, they can also spread within communities if immunization rates fall below the necessary threshold for herd immunity.

The resurgence of these strains in India isn't entirely unexpected. While 2014 marked the official eradication of wild poliovirus, pockets of low immunisation coverage have persisted. Several factors contribute to this:

• Migration: Rapid population movement, particularly in densely populated areas, can leave children vulnerable if they miss vaccinations.
• Vaccine Hesitancy: Misinformation and distrust in vaccines continue to pose a challenge, leading to some parents refusing or delaying immunisation for their children.
• Logistical Challenges: Reaching remote or underserved communities with consistent vaccine access can be difficult due to infrastructure limitations and geographical barriers.
• Environmental Factors: Dr. Pandav notes, "The virus survives in the faeces of infected children. If sanitation is inadequate and the virus isn't effectively cleared, it can spread and mutate further, particularly in areas with poor hygiene."

Combating the Challenge: A Multi-Pronged Approach

Experts are unanimous in their call for a revitalised national immunisation strategy. Intensified vaccination campaigns, particularly in high-risk areas, are paramount. This includes not only routine immunisation but also supplemental immunisation activities (SIAs) targeting vulnerable populations. These campaigns need to be meticulously planned and executed to ensure maximum coverage.

Beyond vaccination, robust surveillance is crucial. Continued monitoring for poliovirus - including genetic sequencing of any detected strains - allows public health officials to track the virus's evolution, identify outbreaks quickly, and adapt strategies accordingly. Understanding the genetic makeup of circulating strains is vital for determining whether they are VDPV, IAPV, or revertants, and for guiding the appropriate response.

Dr. Pandav stresses, "We need to increase immunisation coverage drastically. We must reach every child with the polio vaccine, and that requires a concerted effort from all stakeholders."

According to recent data from the World Health Organization, India has reported over 170 cases of VDPV since 2022, with significant concentrations in states like Bihar, Uttar Pradesh, and Manipur. The government has responded with intensified vaccination drives, but maintaining momentum and addressing the underlying causes of low coverage are essential for long-term success. The fight against polio, even after eradication of the wild virus, remains a critical public health priority.