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Traveler Summary

Key Points

  • Polio is a viral infection of the nervous and muscular systems, acquired through consumption of fecally contaminated food or water. Polio remains endemic in Afghanistan, Nigeria, and Pakistan.
  • Risk is low to very low for travelers.
  • Symptoms are those of an influenza-like illness and include fever, sore throat, and gastrointestinal upset. Headache, neck, back, and leg stiffness may occur.
  • Consequences of infection include permanent limb or respiratory muscle paralysis.
  • Prevention includes observing standard food and beverage hygiene practices.
  • Routine vaccination with inactivated (killed) polio vaccine (IPV) is given at ages 2, 4, and 6-18 months and then at age 4-6 years. Completely unvaccinated at-risk adults may need an entire series, but every effort should be made to give at least 2 doses, a month apart, prior to travel.
  • Vaccine side effects are most commonly pain and redness at the injection site.
  • A single, one-time adult booster dose is recommended for travel to risk areas, even in those who have had the complete childhood series.

Introduction

Polio is a highly infectious disease caused by viruses that invade the nervous and muscular systems and may cause permanent limb or respiratory muscle paralysis or death. Polioviruses may occur naturally or originate from oral vaccine viruses still used in many countries. Humans are the only known reservoir of the polio virus. No drugs or treatments are available that will cure polio.

Risk Areas

Polio has been eradicated from most countries but remains endemic in Afghanistan, Nigeria, and Pakistan. No other countries have reported naturally occurring polio since 2015. A small number of other countries periodically report circulation of vaccine-derived polio viruses, which may also cause polio disease.

Transmission

Poliovirus is transmitted to others through consumption of fecally contaminated food or water. Mouth-to-mouth transmission can also occur through secretions from the throat early in the course of infection. Transmission is greatest in countries with poor standards of hygiene and occurs throughout the year in the tropics, but peaks in the summer in temperate climates.

Risk Factors

Current risk to travelers is low to very low. Even completely unvaccinated travelers going to a country where polio is still circulating have almost no risk of acquiring clinical polio. Children are most commonly affected in endemic countries.

Symptoms

Most infections do not result in symptoms, but the virus can be shed in stool for several weeks. Mild cases can cause fever, sore throat, gastrointestinal disturbances, or influenza-like symptoms, with recovery within a week. More serious cases result in headache, stiffness of neck, back, and legs, and paralysis (most commonly in the legs); however, 1 in 5 cases involves the throat and chest muscles, affecting swallowing and breathing.

Consequences of Infection

Permanent limb paralysis, fatal respiratory paralysis, or less serious muscular disability can result.

Need for Medical Assistance

An unimmunized traveler going to countries where polio still occurs should seek urgent medical assistance if headache and stiffness of neck, back, and legs, or paralysis develop.

Prevention

Non-vaccine: Observe standard food and beverage hygiene practices. See Food and Beverage Precautions.

Vaccine: An inactivated (killed) polio vaccine (IPV) is available in the U.S. and is given routinely as a childhood vaccination and to certain at-risk travelers. IPV is a component of combination vaccines often used in childhood. Live oral polio vaccine (OPV) is no longer available in the U.S. (although it is still used in some countries).

Travel

Vaccination is recommended for adult travelers who have not completed both a primary series and then 1 additional dose during adult years or whose vaccination status is unknown and who are:

  • Going to risk countries where naturally occurring or vaccine-derived polio virus is circulating
  • Going to Saudi Arabia for Hajj/Umra pilgrimage
  • Residents of or long-stay (more than 4 weeks) visitors in Afghanistan, Pakistan, or Nigeria who are onward travelers to other countries, if they have not completed a primary series and have not received 1 additional dose of polio vaccine between 4 weeks and 1 year of departure from the country.

Persons younger than 18 years who received their last childhood dose 10 or more years previously should receive the adult booster.

Vaccination is required for:

  • Hajj and Umra pilgrims traveling to Saudi Arabia (regardless of age and vaccination status) coming from countries on a defined list of suspected polio-endemic countries.
  • Travelers going to certain polio-free countries that have an entry requirement for travelers coming from countries on a defined list of suspected polio-endemic countries.

Persons with underlying medical conditions or who have concerns about the vaccine should speak to their health care provider before vaccine administration.

Side Effects: Local reactions (pain or redness) may occur at the injection site.

Timing:

IPV is given as follows:

  • Routine, regardless of travel for children younger than 18 years: 3 doses, at ages 2, 4, 6-18 months; a fourth dose at school entry or at age 4-6 years
  • Previously unvaccinated at-risk adults 18 years and older: 3 doses at 0, 1-2, and 6-12 months after the second dose
  • Efforts should be made to administer the first 2 doses prior to travel, but even a single dose is beneficial.
  • At-risk adults with no history of an adult booster or those needing to meet an entry requirement: single dose booster
  • More than 1 life-time adult booster is unnecessary unless for a destination entry requirement, in which case the booster must be given between 4 weeks and 1 year of departure from the origin country.

Revaccination with an IPV primary series may be needed for a child who had been vaccinated with a routine OPV series outside the U.S.