Polio: understand transmission, symptoms and vaccine

What is polio?

Polio (from the Greek polios , gray, and myelos , spinal cord), also known as infantile paralysis or polio , is an acute viral infectious-contagious disease, whose main characteristic is sudden flaccid paralysis, in which the patient suffers weakness or paralysis in a certain part of the body due to reduced muscle tone.

Despite this name, polio is not a disease that affects only children. Thus, adults who have not been immunized are also at risk of infection.

What causes this infection is the transmission of poliovirus, an RNA virus that lives in the intestine, which has three serotypes: I, II and III.

Upon settling in the host, the virus undergoes an incubation period, a period that can vary from 2 to 30 days, taking from 7 to 12 days in most cases. It is a viral disease that can affect the nerves and lead to partial or total paralysis.

In most cases, the patient has few symptoms (subclinical form), and may even be asymptomatic of polio.

Polio can cause the paralytic form of the disease in about 1% of infected patients, being capable of causing permanent sequelae, respiratory failure and leading the patient to death. In most cases, the manifestation of the disease occurs in the lower limbs asymmetrically, that is, in only one of the limbs.

In the late 1980s, it is estimated that the disease was responsible for the cases of approximately one thousand paralyzed children daily, a serious situation that drew the attention of the World Health Organization (WHO). From this, goals for the eradication of the disease until the year 2000 were established.

In Brazil, the guidance given by the WHO was to apply vaccination to 95% of children aged up to 5 years, which worked for a long time.

Although the last case of polio in Brazil took place in the 1990s, vaccination is currently being reinforced by the fact that 312 cities in the country are at risk of returning the disease.

As reported by the Federal Public Ministry (MPF), in these 312 cities, the number of children protected against polio is less than 50%. In addition to these worrying figures, this year, six cases of the disease have been reported, but the diagnosis has not yet been confirmed.

The vaccine is the only way to guarantee the prevention of this disease and that is why it is important for people to know the risks and how important immunization is. In Brazil, it is made available through the Unified Health System (SUS).

In ICD-10, the International Classification of Diseases, polio is found by code A80.

Considering the low rate of vaccination in so many cities in the country and the notifications from the World Health Organization (WHO) reporting new outbreaks of polio in Venezuela, we understand the need to reinforce the risks that this disease causes.

According to the WHO, 1 out of every 200 patients infected with polio suffer from irreversible paralysis. Within this group, 5% to 10% die from complications in the respiratory muscles.

Of 350,000 cases caused by the wild virus in 1988, worldwide, 22 were registered in 2017. Due to this global effort, it is estimated that more than 16 million people were saved. Continue reading and understand more about polio. Good reading

Causes

This disease is caused by poliovirus infection and can be acquired through direct contact from person to person, contact with mucus, phlegm or infected feces. The polio virus enters the body through the mouth and nose, multiplying in the throat and intestinal tract.

Upon reaching the bloodstream, the virus can reach the brain, attacking the nervous system, thereby destroying motor neurons and causing paralysis in the lower limbs.

The patient can even be put to death if the nerve cells that control the breathing and swallowing muscles are infected.

The virus incubation period varies from 5 to 35 days, but the average is 1 to 2 weeks. The virus can also be transmitted by contaminated water and food.

How does the transmission happen?

The virus responsible for polio lives in the intestine and transmission occurs via fecal-oral or respiratory tract, in contact with droplets of saliva, in the act of speaking, coughing or sneezing.

Transmission is a worrying factor especially when it comes to poor housing conditions and poor personal hygiene.

The number of children in the same environment also contributes to greater transmission of the polio virus, as basic hygiene care habits, such as washing hands or avoiding putting objects in the mouth, are not so common.

The spread can also happen due to contamination of water or food by infected feces.

Once installed in the host, the virus begins to multiply. In the beginning, this reproduction takes place in the places where it entered the organism, such as the mouth, throat and intestine. Then, the virus passes into the bloodstream, reaching the central nervous system.

With or without symptoms, the person who is infected eliminates the virus in the stool. Usually, transmission is more common in people who have no symptoms.

What types?

Polio is a disease that manifests itself in different ways, namely paralytic, non-paralytic, abortion, asymptomatic and aseptic meningitis .

Paralytic polio

Paralytic polio is more rare and also the most severe form of the disease. Depending on the region of the body affected, the name of this form of the disease changes, which may be:

  • Spinal cord (spinal polio);
  • Brainstem (bulbar polio);
  • Both (bulbospinal polio).

The signs of paralytic polio are initially fever and headache , but they often resemble the symptoms of non-paralytic polio.

In this type, the involvement of the central nervous system is varied, and paralysis may occur alone or abruptly and without previous symptoms.

In about a week the specific symptoms of paralytic polio appear. Are they:

  • Loss of reflexes;
  • Severe muscle pain or weakness;
  • Loose and flabby limbs, often worse on one side of the body.

In bulbar palsy, common symptoms are motor incoordination, respiratory paralysis and difficulty in swallowing.

Abortive poliomyelitis

Abortive polio occurs in about 5% of cases of the disease, in which symptoms include flu-like conditions accompanied by fever, malaise, sore throat, nausea, vomiting, diarrhea , muscle pain and, in some cases, gastroenteritis .

In this form, the patient does not suffer any damage related to the functioning of the cells of the central nervous system.

As with asymptomatic or inapparent polio, the diagnosis of abortive polio is made by isolating the virus.

Non-paralytic polio

Non-paralytic polio presents the same symptoms as in the paralytic form, but in a more aggravated form. In such cases, the central nervous system can be affected.

One of the symptoms that can occur is painful stiffness in the neck, similar to meningitis. Recovery occurs spontaneously, and remission can occur within up to 10 days.

Asymptomatic

It is the form of polio in which the patient has no clinical manifestation. The diagnosis is made only by specific laboratory tests, being a very frequent form of the disease, occurring between 90% to 95% of infections.

Aseptic meningitis

It is a rarer manifestation, being equivalent to 1% of infections. In it, the patient has the same symptoms that occurred in abortive polio, but later there are signs of meningeal irritation and stiff neck.

Groups and risk factors

Polio is a risk for all people who have not been vaccinated in general, but in some conditions the risk of transmission of the virus is greater. Likewise, in some groups the risk of complications and contamination is also more worrying.

In areas with poor basic sanitation and lack of immunization programs, for example, residents become more vulnerable to poliovirus. This is because it is commonly transmitted by contaminated water and food.

Thus, people who live in areas where there is no sewerage or treated water are at a greater risk of contact with contaminated faeces.

Other common risk factors or groups are:

  • Children up to 5 years old;
  • Pregnant women;
  • Seniors;
  • People with weakened immune systems as carriers of the HIV virus;
  • People who have traveled to an area where polio is common;
  • People who live or care for someone who may be infected with poliovirus;
  • People who removed the tonsils by tonsillectomy;
  • People who experience extreme stress or strenuous physical activity after being exposed to the virus, since exhaustion can depress the immune system and make the body more vulnerable to infection.

In children, polio is a high risk because they have an immune system that is still incomplete, which is why they have a natural deficiency and become more vulnerable to symptoms and possible complications.

Polio symptoms

Not everyone who is infected with the polio virus develops the disease. In most cases, the person’s own immune system is able to fight the virus and prevent it from complications and symptoms. In milder cases, patients may experience only diarrhea and fever for a few days.

Polio becomes a concern when the virus passes from the intestine into the bloodstream. These are the cases in which the patient actually suffers from the disease and the symptoms start to become more intense.

Polio symptoms are quite varied, and may be asymptomatic infections (in 90% to 95% of cases) or severe paralysis (about 1% to 1.6%).

What causes the disease to cause paralysis in only a small percentage, however, is still an unknown factor. There are some associated hypotheses, such as deficient immune system, pregnancy, removal of the tonsils, excessive physical exercise, injuries and intramuscular injections.

The reason why polio is asymptomatic in some patients and severe in others can be explained by factors such as the concentration of the virus in the bloodstream, the presence of antibodies and the strain of the virus.

The most common sign of polio is paralysis, which usually affects the lower limbs and usually occurs suddenly. Along with this symptom, signs such as fever, asymmetry, muscle flaccidity and tenderness usually occur.

The less common paralysis affects the respiratory and swallowing muscles, in these cases there is a risk of life for the patient.

Most people infected with poliovirus develop the non-paralytic type. The signs of the disease can be similar to those of influenza and other mild or moderate viral diseases, lasting from 1 to 10 days. Are they:

  • Fever;
  • Sore throat;
  • Headache;
  • Vomiting and nausea;
  • Fatigue;
  • Back pain or muscle stiffness;
  • Sore throat;
  • Pain or stiffness in the arms and legs;
  • Slow growth;
  • Muscle weakness or tenderness;
  • Meningitis.

When the patient has respiratory failure, signs such as agitation, cough , apathy, rapid and short breathing movements, excessive sweating, cyanosis (bluish-looking skin) and excessive crying (babies).

In addition, in this condition, the patient may end up favoring the onset of diseases such as pneumonia and bronchopneumonia.

Post-polio syndrome

Post-polio syndrome (SPP) is a neuromotor complication that can affect people who have been infected with the polio virus. Typically, SPP occurs in patients who are in their 40s, when they have had polio at least 15 years before.

In this condition, the main symptom is the loss of muscle functions that remained stabilized in the interval between recovery and the appearance of new symptoms.

This syndrome does not happen due to a reactivation of the virus, but rather due to the wear and tear of motor neurons very close to those that were destroyed by the poliovirus when the disease manifested itself.

This is because neurons that have remained unharmed by the virus previously try to make up for the lack of those that have been damaged, thus starting to send off branches to innervate the compromised bundles.

The diagnosis of this condition is made by the persistence of symptoms for more than a year in people who have had polio in the past.

An exam that contributes to confirming the diagnosis is electroneuromyography. It helps to assess changes in innervation and helps to exclude the possibility of other degenerative diseases being similar.

Common symptoms in patients with SPP:

  • Joint pain;
  • Progressive muscle weakness in the limbs affected by polio;
  • General fatigue;
  • Excessive tiredness;
  • Muscle atrophy;
  • Difficulty breathing or swallowing;
  • Respiratory disorders related to sleep, such as sleep apnea;
  • Cold intolerance;
  • Cognitive problems, such as difficulties with concentration and memory;
  • Depression, anxiety or mood swings.

Diagnosis

The patient with polio symptoms can be diagnosed by doctors of different specialties, such as the physiatrist, infectious diseases, physiotherapist, pediatrician and neurologist. The laboratory diagnosis can be made through specific exams and complementary exams.

When it comes to specific tests, the most common are those that seek diagnosis by isolating the virus.

Virus isolation is a diagnosis made using stool samples from the patient or people who have had contact with the virus in some way. To identify the isolated virus, tests such as seroneutralization using immune sera or using the PCR technique can be performed.

In most cases, antibodies are detected in the blood of infected patients, early in the infection.

From this, an analysis of the patient’s cerebrospinal fluid (CSF) is performed, collected by lumbar puncture, revealing an increased number of white blood cells (mainly lymphocytes), as well as a moderately high level of proteins . The detection of the virus in the CSF, although rare, confirms the diagnosis of polio-paralytic.

If the virus is isolated from a patient with acute flaccid paralysis, it will be tested later by oligonucleotide mapping (genetic impression) or more recently by polymerase chain reaction (PCR) amplification.

These tests determine whether the virus is a wild type , found in nature, or a vaccine type , that is, derived from a type of poliovirus used to produce polio vaccines.

Isolation of the virus is usually done through cell cultures, for this reason monkey kidney cells are used, such as Vero cells.

Other cells used for poliovirus cell culture were Hela cells, cells of a woman named Henrietta Lacks who died in 1951 because of HPV .

She was a kind of involuntary donor of cancer cells. This happened when scientist George Otto Gey discovered that it was possible to grow them by creating the first immortal cell line, a story reproduced even in theaters with the film “The Immortal Life of Henrietta Lacks”.

In addition to the isolation made with the collection of feces, the diagnosis can be made through blood, oropharynx and cerebrospinal fluid. However, in these places, the isolation may be less, due to the circulation of the virus.

Complementary exams

Other ways of diagnosing polio include non-specific tests such as CSF, electromyography and anatomopathology:

CSF (CSF)

This examination, in cases of polio, allows an increase in the number of cells and an increase in proteins to be observed. It is most used when the doctor seeks a differential diagnosis to confirm Guillain-Barré Syndrome or meningitis, diseases that also cause acute flaccid paralysis.

CSF, or cerebrospinal fluid examination (CSF), is an examination in which the doctor collects cerebrospinal fluid from the lumbar region or the suboccipital region, at the nape of the neck.

No special preparation is necessary to perform this exam, the patient should not be using any anticoagulant medication or drugs that may interfere with blood clotting.

It is an exam that can be done in the face of any disease that may involve the central nervous system, but in most requests, the CSF is done to diagnose cases of meningitis.

Electromyography

Electromyography is an exam that studies the responses produced by muscle fibers and membranes when they are subjected to electrical activities.

It is considered a simple and safe examination, performed through the use of electrodes, which can be needle or superficial. These electrodes are responsible for identifying the electrical waves.

In the case of polio, this test seeks to better investigate the electromyographic pattern of the disease, common to a specific group of diseases that affect the lower motor neuron.

It is not a commonly requested test, but it can be done to exclude the possibility of being a case of polio.

Pathology

The anatomopathological examination is basically the macro and microscopic analysis of cells and tissues from the biopsy performed previously by an anatomopathologist. It is not an exam capable of making a diagnosis for certainty, only when there is a suspicious clinical picture.

Can polio cure?

Polio is a disease that can not be cured , but in some cases, depending on the type and location where the patient was affected, complete recovery is possible .

When the disease does not affect the brain and spinal cord, for example, the chances of recovery are more likely, which can happen in up to 90% of cases.

Polio is a worrying disease because it can lead the patient to temporary, permanent paralysis or even death.

Despite the chances of recovery from the disease, in some cases patients end up having to survive with sequelae of the disease, as in the case of paralytic polio

The treatment, however, is not specific, being just an assistance treatment, to reduce the chances of complication of the patient and enable greater comfort during this moment.

What is the treatment?

Polio treatment is considered a supportive treatment, as there is no specific antiviral therapy for poliovirus.

Thus, the focus will be on reducing the feeling of discomfort, accelerating recovery and ensuring the patient’s quality of life.

Although it is not specific, it should be started as soon as possible to avoid complications, otherwise the risk of life that the patient runs becomes greater.

Home care and medical care can help with polio recovery and should be performed frequently and in the long term.

Depending on the symptoms or sequelae left by the disease, the following treatments can be performed:

  • Occupational therapy;
  • Physiotherapy;
  • Support devices, shoes and, in some cases, orthopedic surgery;
  • Portable respirators to aid breathing;
  • Hydrotherapy;
  • Electrotherapy;
  • Massage;
  • Passive movement exercises;
  • Surgeries, such as tendon stretching and nerve grafting.

In the 1920s, when this supportive treatment was less advanced, polio patients with severe respiratory failure were treated with the use of a machine that became known as the steel lung .

This machine, which looks like it came out of a sci-fi movie, was created by Professor Philip Drinker and was used to force air in by exerting pressure to expand the patient’s rib cage.

Drinker’s invention was responsible for saving many lives, as many patients were able to recover after spending some time in the steel lung. For others, unfortunately, the treatment did not have to be just temporary, leading them to spend the rest of their lives on the machine.

Thus, despite saving them, it did not allow a complete quality of life. Today, thanks to the most current vaccination and mechanical ventilation devices, the steel lungs have fallen into disuse.

A steel lung on display at the “Mobile Medical Museum” in the city of Mobile, Alabama, United States.

Prognosis

Polio is a disease with a worrying prognosis. Although in the non-paralytic forms the recovery may be complete, in the paralytic polio type, on the other hand, the chances of more serious sequelae are recurrent. Two-thirds of the patients have permanent residual weakness.

In cases of patients with bulbar palsy, however, the chance of recovery may be greater than that of peripheral palsy, with mortality being approximately 4% to 6%, and may be 10% to 20% in patients with bulbar disease. .

Complications

Depending on the type of polio, complications can be serious. The most common is paralysis itself, in which the patient ends up losing the ability to move the limbs, partially or totally, irreversibly in most cases.

Paralysis can cause deformities in the joints of the hips, feet and ankles, considering the fact that the lower limbs are the most affected.

In some patients, these deformities can be corrected through surgical procedures, but it is not in all countries where the disease continues to circulate that it is possible to have this resource available as treatment.

In addition, muscle paralysis interferes with skeletal functioning, interferes with joint stiffness and causes motor deficiencies. Thus, we can put as a complication of polio the fact that the patient has to live with the sequelae caused by the disease, in addition to the clinical conditions that become impaired.

Complications can be divided into three types:

  • Damage caused by poliovirus, such as residual paralysis itself, musculoskeletal imbalance, impaired growth, deformities in the skeleton that damage the limbs, respiratory failure and intolerance to cold caused by circulatory disorders;
  • Symptoms that arise from the organism’s failure to try to compensate for the period of stability caused by the disease, such as Post-Poliomyelitis Syndrome, in which signs of weakness and fatigue occur;
  • Complications resulting from secondary trauma, such as joint pain, compressive neuropathy and degenerative arthritis.

Below are some of the most frequent complications in patients who have had polio:

Impaired growth

Due to muscle atrophy and bone deformity, children with more severe polio may experience impaired growth.

In cases where the disease affects only one of the lower or upper limbs, the affected limb’s muscles may shrink, leaving the patient with a small limb when compared to the other.

Pains

Patients suffering from paralytic polio may have muscle atrophy as a complication accompanied by chronic pain.

Breathing difficulty

The patient suffers from chest congestion and lung infections, which can cause respiratory failure. In addition, it also affects the heart, in the sense that it needs to pump blood into the lungs. Under these conditions, it is necessary that the patient is under medical supervision, due to the risk of life.

Muscle complications

Muscle complications, in the patient, end up hampering even activities such as food, as they have difficulty swallowing.

In this condition, there is a risk that the patient will choke on food, drink or saliva, which can cause a chest problem that is difficult to treat and that requires the patient to be admitted to a hospital for a period.

Digestive system

It hinders the normal opening of the patient’s intestines, which can suffer from constipation most of the time.

Urinary system

When the bladder is affected, the patient may suffer from urinary tract infection , which can cause the urine to become very concentrated, forming stones (stones) in the urinary system. These stones become a major problem as they can block the flow of urine from the kidneys and damage them extensively.

Nerves of the face

Not very common, polio can affect the nerves that control the muscles of the face, eyes and tongue, for example. This paralysis makes it difficult for the patient to use these muscles properly, which can affect speech as well as vision.

Living together

Patients who have had polio and remained with sequelae can lead a common and independent life. Certainly, in some cases, some adaptations in daily life are necessary, such as the use of crutches, walking sticks or even a wheelchair.

This adaptation, however, can be a difficult process to accept. It is not easy to understand, at first, the limitations caused by an illness, but it is possible to overcome them and lead a normal life like anyone else.

At this point, it is important that the patient has support from loved ones and, if necessary, that he / she undergo psychological counseling.

In the case of children, it is important that parents / guardians encourage them to carry out activities on their own, always promoting their independence.

Knowing, reading or seeing reports of people who are going through or have been through it can be a way to better understand how to deal with the consequences and overcome the difficulties.

Respecting his physical limitations, the polio patient can develop, study, work, play sports and other activities he wishes. They can also think about having children, if they want, because the disease does not affect the reproductive system.

To assist in locomotion, doctors can guide them in the use of devices, orthoses, crutches, walking sticks or wheelchairs. In addition, they can, through physical exercises and physiotherapy, preserve the movements of the affected limbs or to prevent contractures and deformities.

How to prevent?

 

The main form of polio prevention is vaccination . However, in addition to it, it is necessary to prevent yourself by adopting habits that can contribute to prevent the transmission of the virus.

Vaccination

To prevent polio and make it an eradicated disease, vaccination should be applied to all children under the age of five, according to the vaccination scheme and national campaigns that take place annually. In addition to children, it is also recommended that lactating women receive immunization.

Parents and guardians must pay attention to vaccination dates and attend health clinics. Vaccination against polio is administered free of charge by SUS.

The first dose should be taken at 2 months, the second dose at 4 months, the third dose at 6 months, and, after this period, a booster at 15 months.

Individuals with immunodeficiency, in addition to the increased risk of vaccine polio, can eliminate the virus through feces for prolonged periods (months, years), facilitating the occurrence of mutation (“reversal”) and constitutes a risk for people who are not vaccinated.

There are two types of polio vaccine: the Oral Polio Vaccine, or Sabin, and the Inactivated Poliomyelitis Vaccine, also called Salk.

Oral Polio Vaccine (OPV)

This polio vaccine is better known as the droplet dose. It is always associated with the Zé Gotinha campaign, a character created by the Ministry of Health to attract the attention of children to the importance of immunization.

PWV is, therefore, a bivalent attenuated oral vaccine, which means that it is composed of polio viruses 1 and 3. The vaccine contains the presence of both types of live poliovirus, but they are more weakened.

In addition, VOP contains in its composition streptomycin, erythromycin, magnesium chloride , polysorbate 80. L-arginine and distilled water.

It is a vaccine used as a booster at 15 months and four years and annually during the national campaign, for children aged one to four years.

Polio Inactivated Vaccine (VIP)

This type of vaccine, since it is inactivated, does not present any risk of causing the disease, unlike the oral vaccine. It is a trivalent vaccine, as it prevents polio against the three types of virus (1,2 and 3).

Children should receive the VIP, according to the vaccination schedule, when they complete 2 months and be reinforced at 4 and 6 months.

The composition of the vaccine is polysorbate 80, 2-phenoxyethanol, formaldehyde, Hanks 199 medium, hydrochloric acid or sodium hydroxide. It may contain neomycin, streptomycin and polymyxin B, used in the manufacturing process.

The oral polio vaccine should not be used in people with immunodeficiency (including people with HIV ) or in contact with these individuals.

Preventive measures

In addition to vaccination, some preventive measures are welcome, not only to prevent polio, but other infectious diseases.

The transmission of polio occurs through direct contact with the feces or droplets expelled through the mouth of the infected person.

The poliovirus multiplies, initially, in the places where it enters the organism (throat and intestines), then it spreads through the bloodstream, infecting the nervous system.

The multiplication of the virus can cause the destruction of cells (motor neurons), which results in flaccid paralysis. A person who becomes infected with poliovirus may or may not develop the disease.

Poliovirus transmission occurs more frequently from the asymptomatic individual and its elimination is more intense 7 to 10 days before the onset of the initial manifestations, but the poliovirus can still be eliminated for 3 to 6 weeks. Polio has no specific treatment.

The following precautions must be taken:

  • Update your vaccination plans against the disease, regardless of age (child or adult);
  • Adopt preventive measures against diseases transmitted by fecal contamination of water and food (polio, cholera, typhoid, hepatitis A, hepatitis E);
  • Always wash your hands, especially before preparing meals, before eating and after using the bathroom;
  • Try to develop healthy hygiene habits in young children, such as washing your hands frequently, just drinking treated water and checking that tableware and kitchen utensils are clean before use;
  • Pay attention to the lack of sanitation and adequate hygiene measures in the places;
  • Take care of the quality of water for consumption or for preparing food.

Predicted changes in oral vaccination

Despite having collaborated in the eradication of the disease in many countries, the tendency is that the droplet is gradually left a little more aside.

This is because it is made with live attenuated viruses and the injectable one, on the other hand, uses the inactivated virus.

When the disease affects a specific region, the oral vaccine has the advantage of guaranteeing indirect protection for the population that has not been vaccinated.

Upon receiving the droplet, the child receives the live virus in a weakened version. Even so, it is able to reproduce in the child’s intestines and is eliminated in the feces. Thus, this vaccine virus is able to circulate among the community, through water and sewage, enabling the indirect immunization of people who have not received it.

So far, the oral vaccine has many merits. However, her problem lies in the possibility of the virus undergoing some change and causing polio. The chances of occurring are minimal, one case per million, but in countries where the disease has not happened for years, as in the case of Brazil, this estimate can be a problem.

Thus, the most suitable is that the oral vaccine ends up being replaced by using only the injectable vaccine, which has no risk of causing the disease.

According to the WHO and the Global Polio Eradication Initiative plan, the total replacement of the oral vaccine may occur until the year 2020.

In Brazil, the injectable vaccine started to be part of the National Vaccination Calendar only in 2012, replacing the droplet in the first and second doses. In 2016, the third dose, applied at 6 months, also became injectable.

Common questions

Here are some of the most common questions about polio:

Does the vaccine have contraindications?

Vaccination is very important and should be encouraged, however, in some patients certain care must be taken.

In case it is the VOP vaccine, for example, children who have moderate or high fever (above 38 ºC) should postpone the vaccination until their fever improves. Cases of vomiting or diarrhea, however, are not considered situations in which the vaccine is contraindicated, but it is recommended that the dose be postponed or repeated after four weeks.

In people who have an immune system deficiency caused by disease or medication, pregnant women and those close to them, patients who have suffered from anaphylaxis after using components of the vaccine formula and people who developed vaccine polio at the previous dose should not receive this oral vaccine.

In the case of inactivated vaccine, the contraindication applies to anyone who had a severe allergic reaction to the previous dose in relation to any of the components.

How should care be taken by those traveling to an at-risk area?

People who came from a country where polio is not eradicated should receive doses of the vaccine to ensure immunization, this should be done regardless of age. The vaccine dose should be applied immediately when they arrive in the country.

The same goes for people who are going to a risky area. One dose must be applied before the trip and two must be applied later.

However, these measures are performed when the patient has no way of proving in the vaccination card if he has already been immunized according to the schedule. If during childhood, on the correct dates, the person is already vaccinated, these measures are not necessary.

However, taking into account that Brazil is a continental country, this inspection is not always possible.

That is why frequent vaccine awareness campaigns are so essential, especially when dealing with diseases such as polio, a dangerous condition that has remained eradicated for years in the country.

To continue in this way, people cannot fail to get vaccinated and take their children to receive immunization.

What is the vaccine price?

The polio vaccine, in both forms (VIP and VOP), is available free of charge by the Unified Health System.

How long does the transmission period last?

The polio virus can be found in pharyngeal secretions (saliva and sputum) and in feces for approximately 36 to 72 hours after the patient has been infected, regardless of whether the condition has clinical manifestations or is asymptomatic.

The persistence of the virus in the patient’s throat can last for about a week. In the stool, the time is longer, from 3 to 4 weeks.

In cases of people who have been reinfected, elimination takes place in a shorter period. However, within these periods, contact with other people should be more cautious and hygiene measures reinforced.

Can people who received the vaccine donate blood?

Yes , it is only necessary to wait a little. After receiving the polio vaccine, blood donors must wait for four weeks to be eligible for a new donation.

I lost my vaccination card and I don’t remember if I received the vaccine. What should I do?

The vaccination card or card is a very important document and should be kept, if possible, with an identification document. However, some people may end up losing.

In this case, the first step is to go to the unit where you received the vaccines and check the possibility of a duplicate with the vaccination history. According to the Information System of the National Immunization Program (SI-PNI), not all municipalities have this history, but in some it is possible to receive the duplicate with the registration of the doses received.

In places where there is no such history, it is necessary to find out if there is another type of control. If it does not exist, the orientation is that the vaccination schedule is redone.

Many people who lose their vaccination card need to receive the vaccine again, even if they are immunized. To prevent this from happening, it is essential to maintain extra care with this document, to ensure your health and not need to receive vaccines again.

Can people who have been ill for a short time get the vaccine?

If the patient has already received treatment and the disease has remitted, yes . However, it is important that each person has an individual assessment. The contraindications of the polio vaccine do not place a restriction in this regard.

However, it is important to ensure that the person’s immune system is not weakened, which means that it is necessary to wait a little longer to receive the dose.

Is there any special care before receiving the vaccine, such as fasting?

No . To receive the polio vaccine it is not necessary to remain fasting. The recommended care is in relation to cases of fever. Patients in this condition need to wait until they recover completely.

After receiving the vaccine, it is important to watch for adverse signs. If any serious symptoms happen or do not pass quickly, the patient should go back to the doctor.

In the case of lactating women, it is advisable to stop breastfeeding for one hour before and one hour after the vaccine. Thus, the chances of the baby golfing or vomiting are less, eliminating the need to repeat the dose.

What are the chances of an infected person dying?

It is difficult to know, as the mortality rate varies according to several factors, such as age, clinical condition before the disease, treatment and complications, for example.

In general, from 5% to 10% of patients with paralytic polio die from complications of the muscles used in breathing.

In children, the mortality rate can vary from 2% to 5% and be higher than 15% to 30% in adults.

In the case of bulbar polio, which often leads the patient to death due to damage to the respiratory system, the mortality rate can be 25% to 75%, even with respiratory support.

In which countries has polio not been eradicated yet?

According to the World Health Organization (WHO), the countries still considered as a potential risk of spread are Afghanistan, Pakistan, Nigeria and Somalia, where the disease is not eradicated.

Due to low levels of immunity and surveillance, the international organization Global Polio Eradication Initiative (GPEI) lists the following countries as areas of risk:

  • Cameroon;
  • Central African Republic;
  • Chad;
  • Ethiopia;
  • Equatorial Guinea;
  • Iraq;
  • Niger;
  • Myanmar;
  • Lao People’s Democratic Republic;
  • Liberia;
  • Madagascar;
  • Sierra Leone;
  • Southern Sudan;
  • Ukraine.

However, even in countries where the disease has been eradicated for years it is necessary to pay attention. According to the WHO, many countries are vulnerable to importing the virus due to gaps in the vaccination campaign, as in the case of Brazil.


In Brazil, polio was a disease of high incidence, at least until the mid-1980s. However, with measures adopted based on goals established by the World Health Organization, the scenario has changed.

In 1994, the Pan American Health Organization certified the eradication of wild poliovirus transmission in the Americas, after 3 years without a record of virus circulation across the continent.

Now, in 2018, they complete 27 years without cases of polio by wild virus. However, recently, the Brazilian Society of Pediatrics (SBP) issued an alert for the government and the population to take extra care in relation to the disease, as an outbreak of the disease was reported in Venezuela.

Due to the fact that there is an increase in Venezuelan refugees in the country, SBP asks that the attention of authorities be much greater. Another reason for alert was the survey carried out by the Ministry of Health, where 312 Brazilian cities have rates well below expectations in relation to immunization.

Thus, a disease that has been considered eradicated for years becomes a concern again. Knowing this, help to share information about polio and be sure to get immunized. Parents and guardians of children in the vaccination age group, stay tuned to the calendar and help keep the disease eradicated and the population protected. Thanks for reading!

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