Context: 

Recently, Pakistan has confirmed the second case of poliovirus this year.

More on the News

• The Regional Reference Laboratory for Polio Eradication at the National Institute of Health in Islamabad confirmed that a new infection of wild poliovirus type 1 (WPV1) was reported in the Badin district of Sindh.
• The first case of the year was reported earlier from Dera Ismail Khan district in South Khyber-Pakhtunkhwa (KP) province of Pakistan.
• In 2024, Pakistan reported 74 confirmed cases of polio.

About Polio

Poliomyelitis, or polio, is a highly contagious viral disease caused by poliovirus that primarily affects children under the age of 5.

Poliovirus is a non-enveloped, positive sense, single-stranded RNA virus, identified in 1908 by Karl Landsteiner and Erwin Popper.

The virus is transmitted by person-to-person spread mainly through the faecal-oral route or, less frequently through contaminated water or food. 

The virus multiplies in the intestine, from where it can invade the nervous system, leading to paralysis and, in severe cases, death.

There is no cure for polio, it can only be prevented. 

The first polio vaccine to be widely used in humans was developed in the early 1950s by American physician Jonas Salk.

Polio vaccine, given multiple times can protect a child for life. There are two vaccines available:

• Oral polio vaccine (OPV): It is safe and extremely effective, and used in the fight to eradicate polio. There are different types of OPVs that protect against one, a combination of two, or all three different serotypes of polio – types 1, 2, and/or 3. 
• Inactivated polio vaccine (IPV): It consists of inactivated (killed) poliovirus strains of all three poliovirus types.

The World Health Organization (WHO) observe World Polio Day annually on 24 October to raise awareness of the importance of polio vaccination.         

Types of Polio: 

• Wild Poliovirus (WPV): The naturally occurring strain of the virus responsible for most cases of polio.
• There are three strains of wild poliovirus, namely – Type 1, Type 2 and Type 3. For a country to be declared polio-free, the wild transmission of all three kinds has to be stopped. 
• Vaccine-derived poliovirus (VDPV): This occurs when the weakened virus in the oral polio vaccine (OPV) mutates and spreads in communities with low vaccination coverage. It is one of the global challenges for the eradication of poliomyelitis.