Overview

Polio is also known as poliomyelitis, it is a disease condition caused by poliovirus. It affects the brain and the spinal cord, leading to paralysis or death. In most cases, people typically do not show symptoms or have mild symptoms.^1,2,4,5

Poliovirus is highly infectious, and there are three types of variations known as wild poliovirus type 1 (WPV1), type 2 (WPV2), and type 3 (WPV3). Poliovirus types 2 and 3 are non-existent while the wild poliovirus type 1 still exists in a few parts of the world. The most effective way to prevent poliomyelitis is through vaccination. Other ways include practising proper hygiene and understanding the importance of clean water and sanitation.^1,2,3,6,7

Most poliovirus infections are asymptomatic. Before vaccinations, many were affected by the virus as the outbreaks caused paralysis. There is no cure for poliomyelitis. The main treatment plan is managing the symptoms and preventing further complications.  

Polio

Polio is a disease caused by the poliovirus that affects the nerves in the spinal cord and brain. It causes breathing difficulties and can prevent the movement of certain limbs. In some cases, it can also lead to death.^1,2

Types of polio

Abortive polio lasts up to 2-3 days. It causes flu-like symptoms, some of which are: 

• Headache
• Muscle pain
• Sore throat
• Fever
• Nausea
• Loss of appetite
• Vomiting

Non-paralytic polio is a more severe form of the disease where it causes symptoms like: 

• Severe headache
• Stiffness of the neck, arms and legs
• Muscle weakness
• Sensitivity to light
• Reduced reflexes

Paralytic polio the poliovirus attacks the spinal cord and brain. It causes:

• Difficulty in swallowing
• Difficulty in breathing 
• Sensitivity to touch
• Severe pain
• Muscle weakness causing paralysis

Post-polio syndrome: This type occurs when new signs and symptoms or the same symptoms worsen years after the initial poliovirus infection. Common symptoms are:⁸

• Weakness of muscle and joint
• Severe pain
• Difficulty in swallowing
• Fatigue

Causes

Polio is an infectious disease that often spreads due to poor sanitation and contaminated food and water. 

How polio spreads

Polio spreads through coughing and sneezing. Furthermore, it can infect a person through the faecal-oral route and spread in the following ways: 

• Poor sanitation
• Contaminated water and food
• Swimming in contaminated water
• Not washing hands properly with soap and water after going to the bathroom
• Droplets from an infected person spread through coughs and sneezes
• Touching contaminated surfaces
• Being in close contact with a person affected with polio

Diagnosis

The healthcare provider will ask questions about their condition and conduct a physical examination. Polio symptoms may be similar to flu symptoms so the healthcare provider might take samples for diagnosing polio, which include: 

• Blood tests
• Sample from the throat - saliva
• Examination of stool (faeces)

Management and treatment

The treatment is symptomatic. Treatment can only ease the symptoms as there is no cure for polio. 

• Complete rest
• Mechanical ventilation if the person is having difficulty breathing
• Taking painkillers like ibuprofen
• Using heat packs to decrease muscle aches
• Physical therapy helps to reduce bone deformity and loss of muscle function

Complications

Polio causes long-term complications in people affected by the virus, some of them are: 

• Paralysis
• Muscle weakness
• Deformity of bones (caused by muscle shortening)

Prevention

Vaccination and proper personal hygiene protect us from polio. The Polio vaccine is taken during childhood.⁶

Recommended vaccination schedule

Doctors and healthcare providers recommend four doses of polio shots in the following order : 

• The first shot is when the child is 2 months old
• The second shot when the child is 4 months old
• The third shot between 6 and 18 months old
• A booster dose between the ages of 4 and 6 years

Adult vaccinations

Healthcare providers recommend getting vaccinated as an adult if they have never been vaccinated against it before or get a booster dose of the vaccine in these situations: 

• Travelling or living in areas where polio still exists
• Laboratory personnel who might come in contact with poliovirus
• Person treating or assisting patients with poliovirus

Types of polio vaccine

There are two types of vaccine-  inactivated polio vaccine and the live-attenuated (oral) vaccine.

Inactivated polio vaccine

The inactivated polio vaccine (IPV) contains treated or dead polio virus. It cannot cause polio. It has all three polioviruses. People with weak immune systems can take it. If the person is allergic to neomycin or streptomycin (antibiotics), one must inform the healthcare provider, as the person may not be eligible for IPV.⁹

Live-attenuated (oral) vaccine

The oral polio vaccine (OPV) contains live weakened viruses with all three types of poliovirus. The OPV drops are given in the mouth. In rare conditions the oral polio vaccine causes vaccine-induced poliomyelitis therefore, this vaccine is not recommended for people with weak immune systems.

OPV develops an immune response in the intestine where poliovirus multiplies and provides better protection than the inactivated polio vaccine. This vaccine is used in parts of the world where polio occurs naturally and avoided in areas where polio is eradicated.^3,10

Side effects of the vaccine

Some mild allergic reactions or symptoms occur after vaccination, if they worsen you must consult a doctor or healthcare provider. Some of the symptoms are: 

• Fever
• Tiredness
• Drowsiness
• Difficulty in breathing
• Skin rash
• Itching or swelling of the face or lips
• Diarrhoea
• Difficulty in swallowing
• Vomiting
• Loss of appetite
• Pain and swelling in the area of injection (shots)

FAQs

Can polio come back?

Yes, polio can come back after years. It is known as post-polio syndrome. Signs and symptoms of polio can appear years after the person recovered from polio.

Can polio be cured?

People experiencing mild symptoms of polio recover after treatment. Those with severe symptoms are too weak and paralysed and recovery is impossible. 

How is poliovirus transmitted?

Poliovirus spreads through close contact with infected individuals or the oro-faecal route. Poliovirus spreads through improper personal hygiene and droplet infection due to coughing and sneezing. 

Can adults get polio?

Any unvaccinated adult coming in contact with poliovirus can get polio. Polio vaccinations given during childhood provide lifelong immunity.

Summary

Polio is also known as poliomyelitis. It is a disease condition caused by poliovirus. Poliovirus is highly infectious, and there are 3 types of variations known as wild poliovirus type 1 (WPV1), type 2 (WPV2), and type 3 (WPV3). Poliovirus types 2 and 3 have been eradicated and wild poliovirus type 1 still exists in a few parts of the world. The most effective way to prevent poliomyelitis is through vaccination, practising proper hygiene, and understanding the importance of clean water and sanitation. There are two types of vaccine- inactivated polio vaccine and the live-attenuated (oral) vaccine. Four doses of the polio vaccine are given in childhood. Adults can get vaccinated if not vaccinated in childhood or get a booster dose in an area where polio still exists.