Polio is a disease caused by poliovirus. It enters the body through the mouth, usually from hands contaminated with the stool of an infected person. Polio can also be spread by eating food or drinking liquids that are contaminated with the virus. Most people who get infected with polio have no symptoms. However, infected persons without symptoms can still spread the virus and cause others to develop polio. In severe cases, polio can cause paralysis (cannot move parts of the body) and meningitis (infection of the covering of the spinal cord and/or brain). It can kill people who get it, usually by paralyzing the muscles that help them breathe.

 

How many types of vaccine are there?

There are two types of polio vaccines, Inactivated Polio Vaccine (IPV), a shot, and Oral Polio Vaccine (OPV) drops, by mouth. Both of them give immunity to polio. Although, oral polio vaccine (OPV) is better at keeping the disease from spreading to other people, it actually causes polio in few people (about one in 2.4 million). In contrast, inactivated polio vaccine (IPV) does not cause polio. Inactivated polio vaccine (IPV) is formulated in different combinations with diphtheria-tetanus-acellular pertussis (DTPa) or other vaccines.

 

Who should vaccinated oral polio vaccine (OPV) or inactivated polio vaccine (IPV) and when?
 

• All children should get polio vaccine when they are children. They should be vaccinated with 4-5 doses of inactivated polio vaccine (IPV) or oral polio vaccine (OPV) at the following ages:

 

Type of vaccine	Age
	2 months	4 months	6 months	18 months	4-6 years
Oral polio vaccine (OPV)	1st dose	2nd dose (OPV+IPV)	3rd dose	4th dose	5th dose
Inactivated polio vaccine (IPV)	1st dose	2nd dose	3rd dose		4th dose
			In some case who get inactivated polio vaccine (IPV) combination formulations may receive a 4th dose at 18 months of age and 5th dose at 4-6 years of age
Sequential regimen	1st dose IPV	2nd dose IPV	3rd dose OPV	4th dose OPV	5th dose OPV

*** Remark: An inactivated polio vaccine (IPV) should be given at least 1 time in the first 2 doses of polio vaccine.

• Adult who already vaccinated as children, do not need polio vaccine except at higher risk in the following situations:
  • Travelling to polio-endemic or high-risk areas of the world where polio is common.
  • Working in a laboratory and handling specimens that might contain polio virus.
  • Working as a healthcare worker and treating patients who could have polio or have close contact with a person who could be infected with polio virus.

 

• Adults in these three groups should get polio vaccination as the following table.

 

Adults (18 years of age and older) at higher risk	Inactivated polio vaccine (IPV) Immunization
Who have never been vaccinated against polio	3 doses	Two doses separated by 1 to 2 months, and the third dose 6 to 12 months after the second.
Who have had 1 or 2 doses of polio vaccine in the past	1 or 2 doses	Get the remaining 1 or 2 doses. It does not matter how long it has been since the earlier dose(s).
Who have had 3 or more doses of polio vaccine in the past	1 dose	May get a booster dose of inactivated polio vaccine (IPV).

 

Who should not receive oral polio vaccine (OPV) or inactivated polio vaccine (IPV), or should wait?

1. The following group of people should not get oral polio vaccine (OPV)
   • Anyone who has had a severe allergic reaction to a dose of oral polio vaccine or component of oral polio vaccine, including the antibiotics erythromycin, neomycin, streptomycin or polymyxin B.
   • Anyone who is taking long-term steroids or any other drugs that affect the immune system.
   • Anyone who has cancer or is getting chemotherapy.
   • Children who have a caregiver with depressed immune function, taking immunosuppressive medications, or never had any kind of polio vaccine.

Remark: Individuals infected with human immunodeficiency virus (HIV), both asymptomatic and symptomatic, should be immunized with bOPV (Bivalent oral polio vaccine) according to standard schedules.

2. The people should not get inactivated polio vaccine (IPV)
   • Anyone who has a life-threatening allergy to any component of inactivated polio vaccine, including the antibiotics neomycin, streptomycin or polymyxin B, or to the previous polio shot.
   • Anyone who is moderately or severely ill at the time the shot is scheduled should usually wait until they recover before getting polio vaccine. While people with minor illnesses, such as a cold, may be vaccinated.

Remark: OPV should not be given to pregnancy, but IPV can be given to those who are at risk of virus infection or at high risk for exposure and requires immediate protection.

 

What are undesirable effects of polio vaccination?

Mild problems

·        Local reactions at the site of injection (mild and self-limited) ·        Irritability, tiredness, anorexia, vomiting, fever (reported in inactivated polio vaccine use)

Severe problems

·        High fever, febrile seizures, seizures (rare) ·        Allergic/hypersensitivity reactions, anaphylactic shock, anaphylaxis reactions (very rare) ·        Vaccine Associated Paralytic Poliomyelitis (VAPP): severe muscle aches and spasms, weakness, and loss of movement in an arm or leg. (Vaccine associated paralytic poliomyelitis occurs in oral polio vaccine recipients 1 case per 2.4 million doses administered)

 

Drug interaction

Immunosuppressants (e.g. steroids, azathioprine, methotrexate, cyclosporine) that can weaken the immune system may diminish the therapeutic effect of inactivated polio vaccine. Immunosuppressants may also interact with oral polio vaccine because it may result in an increased risk of secondary transmission of infection or may result in interference with the immune response to the live vaccine. Please inform your doctor if you are taking any of these medicines or any other medications.

 

Storage

Oral polio vaccine (OPV)

• Store at -20 degrees Celsius or less until the expiry date indicated on the packing (usually 2 years)
• If it is stored at 2 to 8 degrees Celsius, its stability is about 6 months.

Remark: Observe the vaccine vial monitor if the inner square is the same color as the outer ring or darker than it. The vaccine should not be used.
Inactivated polio vaccine (IPV)

• Store in a refrigerator at 2 to 8 degrees Celsius and do not freeze.

 
References:

• Kulkanya Chokephaibulkit, Keswadee Lapphra, Chonnamet Techasaensiri. Textbook of Vaccines and Immunization, 2019. Bangkok: Division of Vaccine Preventable Diseases, Department of Disease Control; 2019.
• World Health Organization. WHO recommendations for routine immunization - summary tables. Available from: https://www.who.int/teams/immunization-vaccines-and-biologicals/policies/who-recommendations-for-routine-immunization---summary-tables [Accessed 17 May 2023].
• Centers for Disease Control and Prevention (CDC). Polio vaccine: what you need to know. Available from: https://www.cdc.gov/vaccines/hcp/vis/vis-statements/ipv.pdf [Accessed 17 May 2023].
• Pediatric Infectious Disease Society of Thailand. Summary of immunization schedule changes in Thai children, 2022. Available from: https://www.pidst.or.th/A1150.html [Accessed 17 May 2023].
• Pediatric Infectious Disease Society of Thailand. Vaccination schedule in Thai children by the Pediatric Infectious Disease Society of Thailand, 2023. Available from: https://www.pidst.or.th/A1291.html [Accessed 17 May 2023].
• Centers for Disease Control and Prevention. Polio vaccination: Information for healthcare professionals. Available from: https://www.cdc.gov/vaccines/vpd/polio/hcp/index.html [Accessed 17 May 2023].
• World Health Organization. Table 1: Summary of WHO position papers – Recommendations for routine immunization. Available from: https://cdn.who.int/media/docs/default-source/immunization/immunization_schedules/table_1_feb_2023_english.pdf?sfvrsn=c7de0e97_11&download=true [Accessed 17 May 2023].