Continuing Education Activity

Poliomyelitis is a vaccine-preventable disease caused by the poliovirus. This virus is highly infectious, spreading from person to person mainly through the fecal-oral route. The virus's invasion of the central nervous system (CNS) can lead to significant morbidity, including paralysis of the extremities or the diaphragm. There is no cure for polio; therefore, prevention is critical. Today the CDC recommends the polio vaccine series among the list of routine childhood vaccinations. This activity describes the mode of action of polio vaccines, including modes of administration, formulations, adverse event profiles, eligible patient populations, monitoring, and highlights the role of the interprofessional team in the management of these patients.

Objectives:

• Identify the mechanism of action of the trivalent polio vaccine.

• Outline the schedule for polio vaccine administration.

• Review the potential adverse effects of the polio vaccine.

• Summarize interprofessional team strategies for improving care coordination and communication to advance polio vaccination and improve patient outcomes.

Indications

Poliomyelitis (commonly referred to as "polio") is a vaccine-preventable disease caused by the poliovirus.

This virus is highly infectious, spreading from person to person mainly through the fecal-oral route. Children under the age of 5 are most commonly infected. Seventy-two percent of infected children will remain asymptomatic but continue to shed the virus that may infect others. Once ingested, the virus multiplies in the gastrointestinal (GI) tract and can ultimately lead to an acute nonspecific illness, including symptoms such as:

• Sore throat
• Vomiting
• Fever
• Fatigue
• Headache
• Neck stiffness
• Extremity stiffness/pain

Most notably, the virus's invasion of the central nervous system (CNS) can lead to significant morbidity, including paralysis of the extremities or the diaphragm, which occurs in approximately 1 in 200 persons infected. Those with CNS manifestations of poliomyelitis are at particularly high risk of mortality, with 5% to 10% ultimately dying due to diaphragm paralysis.[1] There is no cure for polio; thus, prevention is vital.

An injectable polio vaccine has been available in the United States since 1955, an inactivated (or killed) vaccine that was pioneered by Jonas Salk. Subsequently, Albert sabin introduced a live, attenuated (or weakened) vaccine in 1961.[2] These vaccines ultimately led to the eradication of the disease in the United States by 1979. Today the CDC recommends the polio vaccine series among the list of routine childhood vaccinations.[3]

Specific recommendations regarding vaccine administration in the United States are made by the Centers for Disease Control and Prevention (CDC) and, more specifically, the Advisory Committee on Immunization Practices (ACIP). Recommendations regarding routine childhood immunization against polio include a four-dose vaccine series of inactivated polio vaccine (IPV) given at two months, four months, 6 to 18 months, and 4 to 6 years of age. 

The third and fourth doses must be separated by at least six months. Due to the use of combination vaccines during childhood, some children may receive five doses of IPV, which is considered a safe practice.[4]

Alternate recommendations are provided for catch-up immunization schedules for children or accelerated vaccine series for adults or children traveling to areas of the world where transmission is a higher risk.

There are no routine recommendations for adults regarding the inactivated polio vaccine series, largely because most adults in the United States have been vaccinated as children. Those adults at higher risk of exposure are encouraged to consider the vaccination series. The risk of exposure may be increased by travel to endemic areas, occupational exposure, or contact with known unvaccinated persons. 

The inactivated polio vaccine series is intended to provide protection against all known wild-type strains of the poliovirus, which includes types 1, 2, and 3.[5]

In some areas of the world, routine vaccination practice includes the oral poliovirus vaccine (OPV) rather than inactivated polio vaccine. Both series are comprised of four doses. A key difference is that the oral polio vaccine is a live attenuated virus. A series begun with one formulation may be completed with the other, so long as the individual receives a total of four doses, the last dose is given as a booster between the ages of 4 and 6 years.

Mechanism of Action

Though multiple formulations of polio vaccines exist, only the trivalent inactivated polio vaccine is currently used in the United States. This single-disease immunization is called poliovirus vaccine inactivated. The virus for this formulation is grown on monkey kidney tissue culture and is inactivated by formaldehyde before its incorporation into the vaccine. The vaccine does contain a preservative as well as trace amounts of polymyxin B, streptomycin, and neomycin.[6] It is also available in its inactivated form in the combination vaccines DTaP/IPV/Hib, DTaP/Hep B/IPV, and DTaP/IPV.[7]

Inactivated vaccines provide immunity by supplying the body's immune system with a dose of inactivated antigen. Because this antigen is not alive, it cannot replicate in the host. Inactivated vaccines cannot cause disease; thus, they may be administered to an immunocompromised host. However, their inability to replicate also confers a lesser level of immunity, necessitating multiple vaccine doses. Like all other inactivated vaccines, the inactivated polio vaccine is administered in series.

In contrast, the oral poliovirus vaccine used in other regions of the world is a live attenuated virus. The three strains of the wild-type virus are weakened in a laboratory setting prior to their incorporation into the oral vaccine. This formulation allows the body's immune system to encounter the virus in a less threatening manner and to mount a humoral immune response to protect the recipient from harm with potential future exposures. 

Administration

Immunity to polio may be conferred by using a single antigen inactivated polio vaccine or as part of a combination vaccine. The volume of solution injected for each is 0.5 mL, but the route of delivery differs. While the single antigen inactivated polio vaccine may be administered intramuscularly or subcutaneously, all three combination vaccines should be administered only intramuscularly. The site of administration depends on the patient's age and size, with preference given to the anterolateral thigh in infants and the deltoid in children and adults.

The clinician should check the CDC guidelines for administration regimens based on the following age groups and scenarios:

1. Pediatric immunization for children 6 weeks of age and older
2. Unvaccinated adults with exposure risk
3. Incompletely vaccinated adults with exposure risk

In the case of the oral poliovirus vaccine, single vials contain 0.5 mL of vaccine solution, which is administered with a pipette into the mouth and swallowed by the recipient. No doses of the oral polio vaccine have been given in the USA since the year 2000.

Adverse Effects

Serious reactions following routine immunizations are rare but include hypersensitivity, anaphylaxis, and seizures. The rate of allergic reaction to routine vaccines is 1 per million doses administered. More commonly, the recipient may experience a local vaccine reaction, including erythema or soreness at the injection site. Other uncommon reported minor adverse reactions include irritability, fatigue, anorexia, fever, and vomiting.

Vaccine-derived poliovirus (VDPV) presents a small risk in regions where immunization rates are low and the oral polio vaccine is administered. The live attenuated virus may acquire virulence, thus posing an infectious threat. It is not known to be a complication of the IPV, the only polio vaccine used in the United States for routine childhood vaccinations since 2000.

Contraindications

Inactivated polio vaccine is contraindicated in individuals who have had anaphylaxis following either a previous dose of the vaccine or after taking streptomycin, polymyxin B, or neomycin, as the vaccine does contain trace amounts of these substances. Contraindications also include patients with active, acute febrile illness and hypersensitivity to the vaccine or any of its components, including 2-phenoxyethanol and formaldehyde.

Injectable polio vaccine is both safe and recommended for administration to immunodeficient individuals and members of their household, as it is not a live vaccine. Note that the oral polio vaccine is live and should not be administered to immunocompromised persons.[8]

Inactivated polio vaccine is also safe to administer during pregnancy or to a breastfeeding mother.[9][10]

Adverse reactions following the receipt of the inactivated polio vaccine are reportable to the Vaccine Adverse Event Reporting System (VAERS) per protocol. 

Monitoring

A completed polio vaccine series confers high levels of immunity. After three doses of the standard four-dose series of the inactivated polio vaccine, efficacy stands at 99% to 100%. The fourth and completing dose is given as a booster between the ages of 4 and 6 years of age. No long-term monitoring of immunity is recommended, and no routine post-administration tests are recommended.

Duration of protection is unknown but is suspected to last years after completion of the primary vaccine series.[11]

In regions of the world where polio morbidity is high and immunity is conferred mainly through the oral poliovirus vaccine series, booster doses in addition to the four-dose series may be warranted.

Toxicity

There is no antidote to the polio vaccine, nor have longterm negative effects of the inactivated polio vaccine been recorded.

Toxicity related to the oral polio vaccine is not specific to the formulation, but rather as would be expected with any live vaccine. As previously stated, live vaccines are to be avoided in immunocompromised persons.

Enhancing Healthcare Team Outcomes

The polio vaccine prevents the potentially life-altering effects of polio. The interprofessional healthcare team, including all clinicians (MDs, DOs, NPs, PAs), nursing staff, and pharmacists, must be aware that some parents may be reluctant to provide this vaccination for their children. All team members must work together to educate patients and their families that no long-term adverse effects of the inactivated polio vaccine have been recorded. Furthermore, the complications of acquiring polio can be serious and long-lasting. The

By working as a team and utilizing open communication and data sharing, health professionals can educate the public about the risks and benefits of polio vaccination, overcome vaccine hesitancy, and contribute to patient and public health. Ultimately, by increasing compliance, all members of the community can be protected from this devasting disease. [Level 1]