Polio

Polio is a virus that can be transmitted from person to person, through food or water contaminated with human faeces, or through infected saliva. By attacking the nervous system, it may cause paralysis. It commonly affects children under the age of five, and may result in permanent paralysis. When breathing muscles are harmed, death may occur. The disease is now only found in Afghanistan and Pakistan.  Worldwide, two of the three strains of wild poliovirus have been eradicated. Poliomyelitis is the scientific name or synonym for the disease Polio.

 

• Polio is a crippling and potentially fatal viral infection of the nervous system.

There are three different wild poliovirus strains, each with its own immunological profile:

I. Wild Poliovirus type 1 (WPV1)

II. Wild Poliovirus type 2 (WPV2)

III. Wild Poliovirus type 3 (WPV3)

• All three strains have the same symptoms, which include irreversible paralysis or even death.

• However, due to genetic and virological differences, these three strains are distinct viruses that must be eradicated separately.

• While WPV2 and WPV3 have been eradicated worldwide, WPV1 is still circulating in Afghanistan and Pakistan.

• In 1999, WPV2 was declared eradicated.

 

There are three types of polio infections:

1) Subclinical polio: This type of polio has no symptoms because it does not affect the central nervous system, which includes the brain and spinal cord. The majority of polio cases discovered are subclinical.

2) Non-paralytic polio: Although this type of polio affects the central nervous system, it does not cause paralysis.

3) Paralytic: This is the most serious and rare form of polio, resulting in the patient's complete or partial paralysis. There are three types of paralytic polio:

a. Spinal Polio – This type of polio affects the spine.

b. Bulbar Polio is a type of polio that affects the brainstem.

c. Bulbospinal Polio is a type of polio that affects the spine and brainstem.

 

• The virus is spread from person to person, primarily through the faecal-oral route or, less commonly, through a shared vehicle (for example, through contaminated water or food).

• Children under the age of five are disproportionately affected.

 

• The majority of people who have polio do not feel ill. Fever, tiredness, nausea, headache, nasal congestion, sore throat, cough, stiffness in the neck and back, and pain in the arms and legs are some of the minor symptoms.

• The virus multiplies in the intestine before infiltrating the nervous system and causing paralysis. Because there is no cure for the disease, the patient will be crippled for the rest of his or her life. A vaccine, on the other hand, can easily prevent polio infection.

• Polio infection can result in permanent loss of muscle function in some people (paralysis).

• Polio can be fatal if the breathing muscles become paralysed or if the brain becomes infected.

 

There is no cure, but immunisation can help prevent it.

 

• ORAL POLIO VACCINE (OPV): It is administered orally as a birth dose in institutional deliveries, followed by three primary doses at 6, 10, and 14 weeks, and one booster dose at 16-24 months of age.

• An attenuated (weakened) vaccine-virus is used in the oral polio vaccine (OPV), which triggers an immune response in the body. When a child is immunised with OPV, the weakened vaccine-virus replicates for a limited time in the intestine, allowing the child to develop immunity by accumulating antibodies.

• The vaccine-virus is also excreted during this time. This excreted vaccine-virus can spread in the immediate community (and provide protection to other children through "passive" immunisation) in areas where sanitation is poor, before eventually dying out.

• INJECTABLE POLIO VACCINE (IPV): Under the Universal Immunisation Programme, it is introduced as an additional dose alongside the third dose of DPT (Diphtheria, Pertussis, and Tetanus) (UIP).

• The World Health Organization (WHO) declared India polio-free on March 27, 2014, after no cases of wild polio had been reported in the country for five years.

 

• It's a weakened poliovirus strain that was originally included in the oral polio vaccine (OPV), but has evolved over time to behave more like the wild or naturally occurring virus.

• This means it can spread more easily to people who have not been vaccinated against polio and come into contact with an infected person's stool or respiratory secretions, such as from a sneeze. These viruses have the potential to cause illness, including paralysis.

 

• Polio has made a comeback in 2019, mostly as vaccine-derived polio infection, in countries such as the Philippines, Malaysia, Ghana, Myanmar, China, Cameroon, Indonesia, and Iran. All of these countries had eradicated the virus at some point in the previous two decades.

• Circulating vaccine-derived poliovirus (cVDPV) occurs when routine or supplementary immunisation activities (SIAs) are not carried out properly, leaving a population vulnerable to poliovirus, whether vaccine-derived or wild.

• As a result, the issue is not with the vaccine, but with low vaccination coverage. A fully immunised population will be protected from both vaccine-derived and wild polioviruses.

 

• Rotary International established World Polio Day on the 24th of October to commemorate the birth of Jonas Salk, who developed a vaccine to combat polio.