Oral Poliovirus (OPV) & Inactivated Poliovirus (IPV) vaccines are the predominant vaccine used in the fight to eradicate Poliomyelitis (Polio), a highly infectious viral disease caused by the Poliovirus mainly affecting children under 5 years of age. The virus spreads through person to person contact and can invade an infected person’s brain and spinal cord causing paralysis.
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Polio cases have decreased by over 99% since 1988, from an estimated 350,000 cases then to 37 reported cases in 2016. As a result of the Global effort to eradicate the disease, more than 16 million people have been saved from Paralysis.
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As long as a single child remains infected, children in all countries are at risk of contracting Polio. Failure to eradicate Polio from these last remaining strongholds could result in as many as 200,000 new cases every year, within 10 years all over the world.
Mode of Transmission
The Poliovirus lives in an infected person’s throat and intestines. It enters through the mouth and spreads through contact with the feces of an infected person and sometimes through droplets from a sneeze or cough. An infected person spread the virus to others immediately before and about 1 to 2 weeks after symptoms appear. The virus can live in infected person feces for many weeks which can contaminate food and water in unsanitary conditions. Even without symptoms, people infected with Poliovirus can spread the virus and cause infection in others.
Symptoms
Most people who get infected with Poliovirus (about 72 out of 100) will not have any visible symptoms. Initial symptoms of polio for about 1 out of 4 people with the infection include sore throat, fever, fatigue, headache, vomiting, stiffness in the neck and pain in the limbs. These symptoms usually last 2 to 5 days then go away on their own.
A smaller proportion of people with Poliovirus infection will develop other more serious symptom that affects brain and spinal cord:
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Paresthesia (feeling of pins & needles in the leg)
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Meningitis (infection of the covering of spinal cord and/or brain) occurs in about 1 out of 25
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1 in 200 infections leads to irreversible Paralysis (can’t move parts of the body) or weakness in the arms, legs or both. Among those paralyzed, 5-10% die because the virus affects the muscles that help them breathe.
Thus, Paralysis is the most severe symptom associated with polio leading to permanent disability and death. Even children who seem to fully recover can develop new muscle pain, weakness or Paralysis as adults, 15 to 20 years later. This is called Post-polio syndrome.
There is no cure for polio, it can only be prevented by immunization. Almost all children who get all the recommended doses of Polio vaccine will be protected from polio.
There are 2 types of vaccine that can prevent Polio, Inactivated Poliovirus vaccine (IPV) & Oral Poliovirus vaccine (OPV).
OPV is a live but weakened form of virus which makes the body produce antibodies against it without developing into the disease. Given as oral drops, it protects not only the person who has taken them but also others living around them. IPV, on the other hand, while highly effective, protects only the vaccinated person and not others. It is given by injection.
Basic differences between OPV & IPV:
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OPV |
IPV |
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Route of Administration |
Orally |
Injection |
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Vaccine Property |
Live attenuated |
Killed |
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Protection Level |
Individual as well as community is protected | Offers only individual protection |
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Cost |
Cheap |
Expensive |
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Immunity |
Humoral + Local (Intestinal) |
Only Humoral Immunity |
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Dosage |
2 drops/dose given 5 times before the age of 5 years |
0.5ml IM single dose or 0.1ml Intradermal 2 doses 2 months apart |
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When to give this vaccine? |
At birth, 6, 10, 14 weeks, 18 months and 5 years |
A dose at 2 months, 4 months & 6-18months. A Booster dose at 4-6years |
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When used correctly, both OPV & IPV are safe and effective. In India, every child under the age of five is given OPV drops on special ‘Pulse Polio National Immunization Days’, a Government-led program which aims at eradicating Polio from the country. Although Polio has been completely eradicated from India, it is important to ensure that all children up to 5 years of age are given the OPV drops, which is the only way to assure the protection of your child and community from Polio. Also, you will need to ensure that your baby gets all the immunizations at the right time. Don’t miss a single dose and also check with your doctor about following the National Pulse Polio program.
On the other hand, only IPV has been used in United States since 2000. Since the risk of getting Polio in this country is now extremely low, experts believe that using oral vaccine is no longer worth. According to World Health Organization (WHO), OPV drops are still recommended for use in Polio-endemic countries or where the risk of transmission of wild type Poliovirus is high. India is now Polio free but still under the risk of spread of Polio from neighboring Polio-endemic countries like Pakistan and Afghanistan. Pulse Polio campaigns utilizing OPV drops should not cease even now to maintain herd immunity and Polio free status of the country. So, the schedule following the administration of both IPV and OPV doses which work complementary to each other in Polio eradication drive, is now recommended in India.
Available Brand Name for IPV vaccine
Ipol
Brand Names for Combination vaccines3
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Kinrix- containing Diphtheria, Tetanus, Pertussis (DTaP) & Polio (IPV)
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Pediarix- containing Diphtheria, Tetanus, Pertussis (DTaP), Hepatitis B & Polio (IPV)
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Pentacel- containing Diphtheria, Tetanus, Pertussis (DTaP), Polio (IPV) & Haemophilus influenzae type B (Hib)
Special conditions under which some precaution is a must
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If your child is ill at the time the IPV is scheduled, it is usually postponed until he/she recovers. The OPV on the other hand, can be given even with Fever or Diarrhea. If your baby is unwell, ask your doctor to be sure about what is best for your child.
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The vaccine is not recommended if your child had a severe allergic reaction to a previous IPV shot or has a severe allergy to the antibiotics neomycin, streptomycin or polymyxin B. They may get OPV instead.
Possible Side Effects of Polio vaccine (IPV & OPV)
In most of the cases, there is no problem with the polio vaccine. But if side effects do occur, they are usually mild like temporary redness and pain at injection site for several days. There is a very small chance of an allergic reaction with the vaccine.
There are things that parents can do before, during and after vaccine visits to make them easier and less stressful.
Before the Visit
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Read any vaccine materials you received from your child’s health care professional & write down any questions you may have.
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Learn more about the benefits & side effects of Polio vaccine.
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Take your child’s personal immunization record to your appointment. An up-to-date record tells your doctor exactly what shots your child has already received.
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Get enough food and pacifiers for the baby so that they remain diverted throughout the session.
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You can also remind older children that vaccines can keep them healthy.
During the vaccination
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Hold your child firmly on your lap whenever possible during the vaccination.
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Distract your child by cuddling them and engaging them in their favorite toys. In case of OPV vaccine, the child won’t have to go through the pain.
After the vaccination
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Review any information your doctor gives you about the shots, especially the Vaccine Information Statements that outline which side effects might be expected after Polio vaccination.
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Give your child lots of liquid. It’s normal for some children to eat less during the 24 hours after getting vaccines.
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Use a cool, wet cloth to reduce redness and swelling where the IPV shot was given.
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If a serious reaction appears, the chances of which is extremely rare, it would happen within a few minutes to a few hours of the shot. In such a case, call the doctor and give him the details of what happened.
