The IPV Vaccine

Polio inactivated vaccine

Polio is a disease in children that is caused by the poliovirus. Polio can cause paralysis of legs or can cause weakness of the entire body. This condition is entirely vaccine-preventable. 

Q. How does a person get this virus?

The poliovirus is a highly contagious virus and can spread through the feco-oral route. Most of the infected children (around 72%) remain asymptomatic. However, they can still shed virus and can cause disease transmission.

Q. How do I know I have developed polio?

Initially, the symptoms in a patient infected with the poliovirus are very nonspecific and similar to that of any other viral illness. Patients may develop features like sore throat, fever, vomiting, headache, joint pain, etc.

Sometimes, the virus can invade the brain and spinal cord and this event can cause paralysis of extremities or the diaphragm, causing difficulty in breathing and ultimately causing death in almost 10% of the cases.

Q. How is this condition treated?

Once the disease starts progressing there is no cure apart from symptomatic management. Therefore, prevention is the key.

Q. How do I prevent myself from developing Polio?

Since 1955, an injectable form of polio vaccine has been available in the health centers of the United States. The US government has been able to eradicate the disease itself by 1979. Owing to the success rate of the vaccine, CDC has recommended polio vaccine to be included in the list of routine vaccinations in a child.

This vaccine provides the body with the inactivated viral particles. The immune system recognizes these viral particles and starts forming antibodies to neutralize the viral particles so that whenever a fully functional virus enters the human body it is already prepared to fight off the virus and prevent the disease.

Q. When do the doctors inject the vaccine into my child?

Advisory Committee on Immunization Practices (ACIP) has recommended 0.5mL volume, 4doses to be given starting at 2months, 4months, 6-18months, and finally at 4years of age. There should be a gap of at least 6months between the 3rd and 4th dose. The vaccine is an inactivated polio vaccine (IPV) and can protect against all known strains (types 1, 2, and 3). 

If the child has to travel to the endemic region before completion of the vaccine series then CDC recommends that the child should take an accelerated schedule and the subsequent doses of the vaccine can be taken in the endemic regions itself or upon returning to the country.

Q. How should I protect myself as I am an adult?

Adults usually do not require vaccination like children because of the vaccination done during childhood. However, adults need vaccination if they have to travel to the endemic country or have to handle the suspected specimens in the laboratories, or if the adult is a healthcare worker actively involved in the treatment of a polio patient. 

Unlike the vaccination schedule in children, there are no routine recommendations available for adults. Adults have to consider accelerated vaccine series if they wish to travel to endemic regions. The first should be considered as soon as possible, and the second dose 1-2months later and the last dose 6-12months after the second dose.

Q. How effective is the vaccine?

The vaccine is highly effective and the oral polio vaccine (OPV) and inactivated polio vaccine (IPV) is equally effective. Two doses of IPV can provide 90% immunity to all three types of poliovirus and three doses can provide up to 99% of immunity.

Q, Are there any serious side effects?

Minor reactions to the vaccine may commonly occur. Pain, swelling, and redness may occur at the injection site. The serious side effects are rare, allergic reactions may occur in one case in 1million dose administration. That’s why the vaccine should not be given if the child has an allergy to the 1st dose or if the child has an allergy to medicines like neomycin or streptomycin. 

Oral polio vaccine should not be provided to immunocompromised individuals. Unlike the oral vaccine which contains live attenuated viral particles, the IPV does not carry the risk of paralysis post-administration. 

The oral polio vaccine has been discontinued in the United States since 2000 AD. 

References:

  1. O’Grady M, Bruner PJ. Polio Vaccine. StatPearls [Internet]. 2019 Oct 14.
  2. Polio Vaccination | What You Need to Know | CDC [Internet]. Cdc.gov. 2021 [cited 14 February 2021]. Available from: https://www.cdc.gov/vaccines/vpd/polio/public/index.html