Mumbai, August 22: A two-year-old child in Meghalaya is suspected of having been infected with vaccine-derived polio, thereby raising concern about polio being back in the country. While the rare "polio case" from the northeast state has caused widespread concern, officials of the health ministry stated that the case was vaccine-derived. They also said there was no need to panic as it was not a case of wild poliovirus. Officials also said that vaccine-derive poliovirus is an infection present in a few people with low immunity.

However, Megahalaya is still awaiting the test results from the National Institute of Virology (NIV) in Mumbai and the Institute of Serology in Kolkata. The tests will determine the nature of a poliomyelitis case allegedly reported in a two-year-old boy who lives in a village in West Garo Hills district. The state's health department also aims to ascertain if the case is a circulatory vaccine-derived poliovirus (VDPV) in the community in West Garo Hills or an immunocompromised case in a single child. While official confirmation is awaited, let's understand what vaccine-derived polio is. Mpox in Thailand: Asian Country Reports First Known Case of New Mpox Strain As 66-Year-Old European Tests Positive for Monkeypox Clade 1b.

What Is Vaccine-Derived Poliovirus?

According to the Centers for Disease Control and Prevention (CDC), a vaccine-derived poliovirus or VDPV as it is called is a strain that is related to the weakened live poliovirus contained in the oral polio vaccine (OPV). Although the polio vaccine is safe and has helped most countries eradicate the infection, the weakened virus can revert to a form which can cause illness and paralysis if allowed to circulate in under or unimmunized populations for a long time or replicate in an immunodeficient individual. The CDC also states that OPV is a safe and effective vaccine which contains a combination of one, two, or three strains of live, weakened poliovirus and is given in the form of oral drops.

The CDC further stated that vaccine-derived polioviruses, or VDPVs, emerge when not enough people are administered the polio vaccine. The rarer infection also emerges when the weakened strain of the poliovirus from the oral polio vaccine spreads among under-immunized populations. Dr T Jacob John, former professor of virology at Christian Medical College Vellore, said that OPV could lead to vaccine-derived polio strains in two ways. Firstly, the weakened virus can continue circulating from child to child, thus gaining back its ability to transmit quickly and cause severe infection every time it spreads. Chandipura Virus Causes, Symptoms and Treatment: All You Need To Know About the Virus That Causes Severe Inflammation of the Brain.

Secondly, the vaccine's virus can cause chronic infection in children who have weakened immune systems, thereby replicating in their gut for years and slowly gaining its ability to cause severe infection. In the past, vaccine-derived polio cases have been reported in the country. In 2013, an 11-month-old immuno-deficient child from Maharashtra’s Beed district died of VDPV. The rare poliovirus was also reported in a 2.5-year-old child from Delhi. However, these are not the only incidents of vaccine-derived polio cases from the country.

(The above story first appeared on LatestLY on Aug 22, 2024 06:10 PM IST. For more news and updates on politics, world, sports, entertainment and lifestyle, log on to our website latestly.com).