Polio which is also referred to as poliomyelitis or infantile paralysis is an infectious illness caused by the poliovirus. The poliovirus is divided into three types which affect the body differently. The poliovirus is mainly spread through contact with food, water or hands that are contaminated with the feces or throat secretions of an infected person.
In most instances, a patient-first experience muscle weakness resulting in them being unable to move at the onset of the disease. In most cases, this occurs over a few hours or a few days after one has been exposed to the pathogens. Other symptoms may include mild, flu-like symptoms to life-threatening paralysis.
In one to two percent of cases, infantile paralysis affects the nerves, resulting in paralysis of the arms, legs or the diaphragm (that controls breathing). Between two and five percent of people who develop paralytic polio will die. Half of those who survive will have permanent paralysis.
The post-polio syndrome occurs years after an initial bout of polio, with new symptoms of weakness, joint and muscle pain, and fatigue.
Causes of Polio
The poliovirus is spread when food, water or hands that are contaminated with the feces (poo) or the throat or nasal secretions of an infected person enter the mouth of an uninfected person.
A person may develop symptoms within three to 21 days of coming into contact with the virus and will be most infectious seven to 10 days before and after the beginning of symptoms. People remain infectious for as long as the virus continues to be excreted in their feces (poo), which may continue for several weeks. Typically, the virus remains in the throat for one to two weeks.
Symptoms of Polio
Infantile paralysis symptoms generally appear between three and 21 days after infection. However, many people infected with poliovirus have no symptoms and may not even know they are affected.
In mild polio cases, symptoms include:
- tiredness and weakness (malaise)
- nausea and vomiting
- muscle stiffness.
If the virus spreads to the nervous system, major illnesses such as meningitis (brain infection) and paralysis can occur. The onset of paralysis is generally quite rapid – usually within three to four days. Symptoms include:
- severe muscle pain
- stiffness of the neck and back – with or without paralysis
- swallowing and breathing problems
- long-term disability – due to paralysis of the muscles
- death – in severe cases, when breathing and swallowing muscles are paralyzed.
Diagnosis of polio
Diagnosis involves a doctor taking a medical history and performing a physical examination for symptoms such as neck and back stiffness, abnormal reflexes, and swallowing and breathing problems. The diagnosis also attempts to rule out other possible explanations for symptoms.
To confirm the diagnosis, the doctor will take a sample of throat secretions, feces or the fluid surrounding the brain and spinal cord (cerebrospinal fluid) to test for the poliovirus.
Risk factors for polio
You are most at risk of infection with the poliovirus if you haven’t been immunized against infantile paralysis. Pregnant women, the elderly, the very young and people with a weakened immune system, such as those with HIV, are especially susceptible to infection. This is especially the case in parts of the world where sanitation is poor and immunization programs are not widespread.
Factors that can increase your risk include:
- traveling to an area where infantile paralysis is common or where an outbreak has recently occurred
- living with or caring for someone who may be infected with the poliovirus
- being unimmunized and having contact with someone recently immunized with the oral infantile paralysis vaccine.
Immunization against polio
Immunization is the best protection against infantile paralysis and is recommended for all infants, children, and adults. The polio vaccine is combined with vaccines for other infectious diseases when given to children at two, four and six months and at four years of age. Adults should have had at least three doses of polio vaccine in the past.
Protection against infantile paralysis is available free of charge under the National Immunisation Program Schedule. In Victoria, immunization against polio is free for:
- Babies at two, four and six months – immunization in the form of diphtheria, tetanus, whooping cough, hepatitis B, polio and Haemophilus influenzae type b (Hib) vaccine (six-in-one vaccine)
- Children at four years – a booster dose in the form of diphtheria, tetanus, whooping cough, infantile paralysis vaccine (four-in-one vaccine)
- Children up to and including nine years of age – catch up immunization with combination vaccines is available.
- Aboriginal and Torres Strait Islander people, refugees and asylum seekers from ten years of age – catch-up immunizations with a polio-only vaccine are available for people who have not been fully vaccinated.
All adults should make sure that they have been vaccinated against infantile paralysis. Adults having the polio vaccine for the first time should receive a course of three injections with an interval of four weeks between the doses. If you have not received at least three doses of the polio vaccine, speak to your doctor about catch-up doses.
Adults do not need a booster dose unless they are at special risk. You are at risk and should arrange with your doctor to get a booster if you:
- intend to travel to areas where infantile paralysis is present – check with your doctor if you are traveling outside of Australia, especially to Nigeria, India, Pakistan, Afghanistan, Angola or Chad
- are a healthcare worker where contact with people with infantile paralysis is possible
- are likely to handle laboratory specimens that contain live poliovirus.
Treatment for polio
There is no cure for infantile paralysis. Treatment aims to manage the effects of the disease. Supportive treatment options include:
- antibiotics – for secondary infections
- pain-relieving medication
- portable ventilators to assist breathing
- medication to reduce muscle spasms
- moderate exercise
- heat treatments
- a nutritious diet.
Long after the initial bout of poliomyelitis, some people suffer from further symptoms including new weakness, joint, and muscle pain and fatigue. These symptoms are known as the ‘late effects of infantile paralysis’ or ‘post-polio syndrome’. Not everyone who has had infantile paralysis will develop post-polio syndrome. People who were severely paralyzed by infantile paralysis are more commonly affected, with approximately 20 to 40 percent of people who had paralysis developing late effects.
Symptoms of post-polio syndrome
Late effects of polio can develop years or decades after the initial bout of infection. The most common symptoms include:
- decreasing strength and endurance
- breathing, swallowing or speaking difficulties
- pain in muscles and joints
- fatigue and an inability to stay alert.
Causes of post-polio syndrome
The late effects of the post-polio syndrome are not caused by re-infection with the poliovirus. Scientists believe that post-polio syndrome could develop because:
- Nerve cells that control muscle movements were damaged by the initial polio infection.
- Some of the nerve cells recovered, while others ‘sprouted’ new nerve fibers that work hard to take over the work of nerves that died.
- After many years of increased workload, the sprouted nerve fibers start to break down. As a result, new muscle weakness is experienced.
Diagnosis of post-polio syndrome
There is no test that will definitely show that you have post-polio syndrome. The diagnosis is based on medical history. The medical history of a person with the post-polio syndrome will include:
- a polio infection in the past – with or without paralysis
- new symptoms of pain and weakness
- no other clinical explanations for the symptoms.
Treatment for post-polio syndrome
There is no specific treatment for post-polio syndrome. Symptoms may be controlled or improved if you:
- avoid physical overexertion or stress
- keep comfortably warm and avoid exposure to cold temperatures
- modify daily activities to conserve energy – for example, sit rather than stand at a workbench
- use calipers, braces, walking sticks, and electric scooters
- ensure that all exercise is pain-free and does not cause excessive tiredness.
Surgery can relieve a number of problems, such as:
- a torn rotator cuff tendon in the shoulder – this can occur after years of using the arms to push up and out of wheelchairs
- foot deformities that can cause falls.
The onset of the late effects of polio can cause many people to feel emotional about past polio experiences. Joining a support group may help.
Rehabilitation for post-polio syndrome
After a full assessment with a rehabilitation specialist, you may be referred to:
- a physiotherapist – for weakness, pain or mobility problems
- a respiratory therapist – for breathing difficulties
- an orthotist – for leg braces
- an occupational therapist – for help with functioning at work, home or in the community
- a speech pathologist – for help with speaking or swallowing
- a pain clinic – for chronic pain
- a psychologist – for depression or other mood difficulties.
As people with the late effects
Frequently Asked Questions About Polio
What is polio?
Poliomyelitis (polio) is a highly infectious disease caused by the poliovirus. It invades the nervous system and can cause paralysis or even death in a matter of hours.
How is polio transmitted?
Poliovirus enters the body through the mouth, in water or food that has been contaminated with fecal material from an infected person. The virus multiplies in the intestine and is excreted by the infected person in feces, which can pass on the virus to others.
What are the symptoms of polio?
Initial symptoms of infantile paralysis are:
- Stiffness in the neck
- Pain in the limbs
Who is at risk of catching polio?
infantile paralysis mainly affects children under 5 years of age.
What are the effects of polio?
One in every 200 persons infected with infantile paralysis leads to irreversible paralysis (usually in the legs).
Among those paralyzed, 5%-10% die when their breathing muscles are immobilized by the virus.
Is there a cure for polio?
No there is no cure for infantile paralysis. Polio can only be prevented by immunization. Safe and effective vaccines exist – the oral polio vaccine (OPV) and the inactivated polio vaccine (IPV).
What is the Global Polio Eradication Initiative?
The Global Polio Eradication Initiative (GPEI) is a partnership that aims to consign infantile paralysis to the history books. It is led by national governments with five partners – the World Health Organization (WHO), Rotary International, the US Centers for Disease Control and Prevention (CDC), the United Nations Children’s Fund (UNICEF), the Bill & Melinda Gates Foundation and Gavi, the Vaccine Alliance. Since the GPEI was founded, polio cases have fallen worldwide by over 99%. As recently as 30 years ago, 1000 children EVERY SINGLE DAY were paralyzed by polio. By 2015, all countries but two had stopped polio transmission, and the wild poliovirus was geographically constrained and caused 74 cases of wild poliovirus in the entire year. Failure to eradicate polio, however, will lead to a global resurgence of the disease. Within ten years, 200 000 new cases could occur every single year, all over the world. That is why it is critically urgent to complete the job of polio eradication once and for all.
Where does wild poliovirus continue to circulate today?
There are just three countries that have never stopped infantile paralysis transmission – Afghanistan, Nigeria, and Pakistan. However, infantile paralysis can and does spread from these countries to their neighbors and beyond. It must be remembered that polio anywhere is a threat to children everywhere. It does not respect borders or social class and travels with ease.
Could polio spread to other polio-free countries?
Polio does not respect borders – any unimmunized child is at risk. For every case of paralysis, there are between 200 and 1000 children infected without symptoms. So it is hard to detect infantile paralysis and hard to prevent the virus from traveling. Children living in areas where immunity levels are low are particularly vulnerable. The best defense against polio importations is to eradicate the virus. Only then will all children be safe.
What will it take to eradicate polio?
To stop infantile paralysis we need to:
- Engage entire societies in the effort to reach every last child
- Make special plans to reach children from mobile and migrant populations, in conflict zones, or in remote regions
- Strengthen routine immunization, which is the best national defense against polio
- Improve surveillance in high-risk areas
- Encourage governments to reach out to the poorest people with other public services
- Continue to receive the highest level of political commitment from national governments and multilateral institutions
- Ensure the needed financial resources are in place to finish the job.
Why is so much focus placed on polio, but not on other diseases?
Polio is one of only a few diseases that can be completely eradicated, such as was the case with smallpox. By eradicating polio, children across the entire world will benefit, and no child need ever again know the pain of polio-paralysis. Most diseases, such as HIV and malaria, for example, cannot be eradicated, because the tools to eradicate these are not available. Polio does not have an intermediate host (i.e. it does not affect animals, and the virus cannot live in animals, in the way that malaria, for example, does in mosquitoes), a safe and effective vaccine is available to protect children from polio, it does not survive for extended periods of time in the environment, and while it is contagious, its infection period is relatively short. Infantile paralysis eradication activities are also strengthening routine health services. Thanks to polio eradication activities, an active disease surveillance network have been established in all countries, into which other diseases – including measles – are now being integrated. Polio eradication infrastructures are also used for the provision of other health services such as deworming tablets, vitamin A and bednets.
Why are children given oral polio vaccines?
Polio vaccine is the only protection against infantile paralysis, a paralyzing disease for which there is no cure. It is essential that every child under five is immunized against infantile paralysis. Oral polio vaccine is safe and effective, and because it is administered orally, it can be given by volunteers. Its method of action ensures that person-to-person spread of the virus can be interrupted.
Does the oral polio vaccine have any side effects?
Oral polio vaccine (OPV) is one of the safest vaccines ever developed. It is so safe it can be given to sick children and newborns. It has been used all over the world to protect children against infantile paralysis saving at least 16 million children from permanent paralysis by infantile paralysis. On extremely rare occasions, the attenuated virus in the oral polio vaccine can mutate and regain virulence. However, children are far more at risk from polio than any side effects of the polio vaccine.
What is the Islamic guidance on the polio vaccine?
Oral polio vaccine (OPV) is safe and has been declared halal by Islamic leaders all over the world – the Grand Sheik Tantawi of Al-Azhar University, the Grand Mufti of Saudi Arabia and the Majelis Council of Ulemas in Indonesia.
Is it safe to administer multiple doses of OPV to children?
Yes, it is safe to administer multiple doses of infantile paralysis vaccine to children. The vaccine is designed to be administered multiple times to ensure full protection. In the tropics, several doses of infantile paralysis vaccine are required for a child to be fully protected – sometimes more than ten. This vaccine is safe for all children. Each additional dose further strengthens a child’s immunity level against infantile paralysis.
How many doses of OPV does a child need before they are protected?
The oral polio vaccine needs to be administered multiple times to be fully effective. The number of doses it takes to immunize a child depends entirely on the child’s health and nutritional status, and how many other viruses that child has been exposed to. Until a child is fully immunized they are still at risk from infantile paralysis. This just emphasizes the need for all children to be immunized during every round of national immunization days. Every missed child is a place for the poliovirus to hide.
Should a child receive OPV during polio campaigns and routine immunization?
Yes. Oral polio vaccine (OPV) is safe and effective and every extra dose means a child gets extra protection against infantile paralysis. It takes multiple doses of OPV to achieve full immunity against infantile paralysis. If a child has received the vaccine before, then extra doses given during the National or Sub National Immunization Days (NIDs/SNIDs) will give valuable additional immunity against infantile paralysis.
Is OPV safe for sick children and newborns?
Yes. Oral infantile paralysis vaccine is safe to be given to sick children. In fact, it is particularly critical that sick children are immunized during the campaigns, and newborn babies, because their immunity levels are lower than other children. All sick children and newborns should be immunized during the coming campaigns to give them the protection against infantile paralysis that they desperately need.
What is the role of Inactivated Polio Vaccine (IPV)?
Every country in the world except two (Sweden and Iceland) used oral polio vaccine (OPV) to eliminate infantile paralysis and continued using OPV, usually until the late 1990s, when some switched to inactivated infantile paralysis vaccine due to progress towards infantile paralysis eradication (when the risk of wild poliovirus was diminished). Most countries use OPV as it has a unique ability to induce intestinal, local immunity, meaning that it can actually interrupt wild poliovirus transmission in an environment. This is not possible with IPV, an inactivated infantile paralysis vaccine, which induces only very low levels of immunity to poliovirus inside the gut, and as a result, provides individual protection against infantile paralysis, but unlike OPV, cannot prevent the spread of wild poliovirus. IPV is being introduced into all routine immunization programs around the world, as part of ongoing activities for the phased removal of OPVs.
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