Introduction

Polio was once one of the most feared diseases in the world. Thanks to the effective vaccination efforts, its incidence has decreased by over 99% since 1988.¹ Unfortunately, in some developing countries such as Pakistan and Afghanistan, polio remains a serious threat, particularly for those who are most vulnerable.^2,3 In this article, you'll read about: 

• Brief explanation of polio
• Risk factors of polio and high-risk populations in developing countries
• Prevention of polio and protection from infected people

What is polio?

Polio, short for poliomyelitis, is a highly contagious disease caused by a virus known as poliovirus. The infected person can transmit the virus to another person through respiratory droplets produced by coughing and sneezing. However, it is transmitted by the feco-oral route more commonly.⁴ You may get infected by contact with the faeces of an infected person or by having food and water contaminated by them.

What are the symptoms of polio?

People infected by poliovirus experience a range of symptoms, with most of them being asymptomatic (having no symptoms).⁴ Some may experience mild flu-like symptoms such as fever, fatigue, headache, vomiting and sore throat, which last for 2 to 3 days. This type of polio is known as abortive polio.⁴ 

In non-paralytic polio, these flu-like symptoms last longer than a few days. Along with that, you may also have pain or stiffness in your neck, arms or legs. Poliovirus may attack your nervous system (brain and spinal cord) in more severe cases, known as paralytic polio. This, in turn, leads to paralysis of muscles that are involved in speaking, swallowing, breathing and movement of your limbs.⁴ 

What are the complications of polio?

These are the complications that may occur if you are infected with poliovirus. 

• Muscle paralysis, which causes trouble in moving your limbs, swallowing or breathing. In rare cases, death may occur due to breathing difficulties
• Inflammation of the  brain (encephalitis) or the membranes lining the brain and spinal cord (meningitis)
• Chronic pain and limb deformities
• Post-polio syndrome—It is a condition in which you feel sick years after recovering from polio. The symptoms may include progressive muscle weakness, joint pain and sleep apnoea

General risk factors for severe polio complications

Certain conditions can increase your chances of getting polio and developing complications, especially when combined together. These are described below:

Age

WHO says that young children, particularly those who are under 5 years of age, are more prone to getting infected by poliovirus. It may be due to the reason that their immune system is weak and is still developing.

Incomplete or no vaccination

Make sure to have your child fully vaccinated according to the schedule. In developing countries, children are either not vaccinated or have not completed their course of vaccination. It may be due to several factors such as lack of access to healthcare facilities, misinformation and myths surrounding vaccination.⁵ This increases their risk of getting polio.⁶

Environmental conditions

Since polio is transmitted by eating food contaminated by faeces of affected people, poor hygiene and sanitary conditions play a major role in spreading poliovirus, according to WHO. In addition to that, crowded living conditions, limited access to clean water, and unsafe waste disposal further worsen the problem, putting entire communities, especially children, at risk of infection.

Poor nutrition

Diet is a really important aspect of your lifestyle, particularly in maintaining your overall health and well-being. It can either protect you from diseases or increase your vulnerability, depending on your eating habits. When you do not get enough nutrients through your diet, such as vitamins, minerals, and proteins, your immune system weakens. This makes you more susceptible to infections, including poliovirus, potentially leading to severe complications.⁷

Weakened immunity

If you are having certain medical conditions that compromise your immune system, such as AIDS, cancer or diabetes, they can make you more susceptible to infections. Children born with congenital diseases (these are the conditions that they are born with) are also more at risk of getting infected with poliovirus.

High-risk population in developing countries

All the risk factors described earlier are highly prevalent in developing countries, making polio still a continuing threat in these regions, despite global efforts towards eradication. Along with them, shortage of trained health workers and low health literacy are also contributing factors.

Another concern is a rare version of the poliovirus known as vaccine-derived poliovirus (VDPV). This strain can cause infection in areas where people are not fully vaccinated. It happens when the weakened virus present in the oral polio vaccine (OPV) starts spreading. If many people in an area are not vaccinated, VDPV tends to change and mutate and thus causes illness.^8,9

When to seek medical help

Early symptoms of polio, such as headache, fever, nausea, and vomiting are very similar to other viral infections and are usually ignored. See your healthcare provider if you have any of these symptoms and get an accurate and timely diagnosis to avoid complications.¹⁰

If you have had polio before and now you are experiencing any new symptoms like weakness in your arms and legs, breathing difficulties or any other symptoms, immediately report to your doctor.¹⁰

Prevention

There is no cure for polio. Vaccination remains the best and most effective method of prevention. There are two types of polio vaccines, oral polio vaccine (OPV) and inactivated polio vaccine (IPV).⁸ OPV, as the name suggests, is given through the mouth, and it contains poliovirus in its weakened form. IPV, on the other hand, is given through injection in your arm or leg and it contains inactivated or killed poliovirus virus. The site where the injection is given depends on your age. Here are the CDC (centers for disease control and prevention) recommendations for polio vaccination for different age groups.¹⁰ 

For children

According to the CDC, children should receive four doses of IPV as a part of routine childhood immunisation at the following ages:¹⁰

• First dose at the age of 2 months
• Second at 4 months
• Third, between 6 to 18 months
• Fourth between 4 to 6 years

Talk to your healthcare provider if your child is missing any dose.

For adults

Polio vaccination is a part of routine childhood immunisation. If you received vaccinations as a child, you are very likely already protected against polio. However, there are certain conditions in which you need to receive a lifetime booster dose of IPV even if you are fully vaccinated. These conditions may include:¹⁰

• When you are travelling to a country where polio is still present 
• You are a laboratory worker, and you may have to deal with specimens containing poliovirus
• You are a healthcare worker, and you may contract the disease while dealing with people having polio

For people who are not vaccinated, CDC recommends 3 doses of IPV with the second dose given 1 to 2 months after the first one, and the third dose given 6 to 12 months after the second one.¹⁰

Other protective measures

Even though vaccination remains the most effective way to protect yourself from polio, you can also make some healthy changes in your lifestyle, like washing your hands regularly, drinking clean water, and eating healthy and nutritious foods. These not only protect you from polio, but also play a major role in your overall health and well-being.¹⁰

Summary

Polio may seem like a disease of the past, but in many developing countries, it is still a major concern, especially for people who are most vulnerable. If you or your child haven’t received full vaccination, are malnourished, or have a weakened immune system, you’re at a higher risk for severe complications like paralysis or trouble breathing. Children under the age of 5, people living in poor sanitary conditions, and those in areas with low vaccination rates are especially at risk. 

Getting vaccinated offers the best defence against polio. Try to stay up to date with your polio vaccinations, practise good hygiene, and make sure to have a good and healthy diet. These measures can play an important role in protecting both you and your community from polio. Since there is no cure for polio, doctors usually recommend medications to relieve symptoms, like they may prescribe painkillers or advise physiotherapy for muscle weakness.