Adults and children who are unvaccinated or not up to date on polio vaccinations should get a booster or complete their series before traveling to countries where poliovirus is now being reported, according to the Centers for Disease Control and Prevention.
Some travelers, regardless of immunization status, may also be required to obtain a booster dose before leaving the infected countries: Afghanistan, Nigeria, and Pakistan – where polio is endemic – and Cameroon, Ethiopia, Equatorial Guinea, Iraq, Israel, Somalia, and Syria, where wild poliovirus is now circulating.
© BananaStock /Thinkstockphotos.com
Adults who have completed a routine polio vaccination series are considered to have lifelong immunity, CDC officials said.
"Travelers working in health care settings, refugee camps, or other humanitarian aid settings in these and neighboring countries might be at particular risk for exposure to wild poliovirus," Dr. Gregory S. Wallace and his colleagues reported in the July 7 issue of the Morbidity and Mortality Weekly Report.
Adults who have completed a routine polio vaccination series are considered to have lifelong immunity, although supporting data for this assumption are currently lacking. Adults who are unvaccinated or incompletely vaccinated, or whose status is unknown, need to have at least one inactivated polio vaccine for short-notice travel, and up to three if travel is at least 8 weeks away, wrote Dr. Wallace, who leads the CDC’s measles/mumps, rubella, and polio team, and his coauthors.
Unvaccinated or incompletely vaccinated infants and children should have an accelerated series before traveling to infected countries. The first dose should be given to infants who are at lest 6 weeks old and both the second and third at least 4 weeks after the previous doses. However, the minimum interval between doses three and four should be at least 6 months (MMWR 2014;63:1-4).
The recommendations should also prevent travel problems that could face unvaccinated or incompletely vaccinated persons who are trying to enter or leave an infected country, Dr. Wallace and his colleagues noted. The World Health Organization may shortly implement vaccination requirements for these countries.
Countries known to be exporting wild poliovirus (Cameroon, Equatorial Guinea, Pakistan, and Syria) should ensure complete vaccination of departing residents and travelers with visits of at least 1 month. The other six infected countries "should encourage polio vaccination boosters among departing residents and long-term travelers," according to the CDC.
This recommendation could change at the end of July when WHO reassesses the polio public health emergency officials called last spring.
To help avoid problems, the CDC recommends that all polio vaccinations be documented on an International Certificate of Vaccination or Prophylaxis (the "yellow card"). Even children who have a complete polio series should receive a booster before they leave an infected country. Adults with documentation of a series may also be required to receive a booster before leaving.