Although polio has been eradicated as an endemic illness within the United States, that isn’t true for different elements of the world.
The US Centers for Disease Control and Prevention issued a Level 2 travel notice on March 9 warning that poliovirus continues to flow into in a number of elements of the world and advising vacationers to take enhanced precautions. The company really helpful that vacationers to affected international locations guarantee they’re absolutely vaccinated towards polio earlier than departure.
Despite its eradication within the United States, well being officers say worldwide journey can nonetheless pose a danger when the virus is circulating elsewhere. Because poliovirus spreads simply and may transfer throughout borders by way of contaminated vacationers, sustaining excessive vaccination protection stays important.
What precisely is polio, and the way does it unfold? If the United States now not has ongoing transmission, why are journey alerts nonetheless vital? Which elements of the world are seeing poliovirus circulation now? Should vacationers examine their vaccination standing earlier than worldwide journeys? If somebody is uncertain whether or not they’re absolutely protected, what ought to they do subsequent?
I spoke with NCS wellness knowledgeable Dr. Leana Wen to discover out. Wen is an emergency doctor and adjunct affiliate professor on the George Washington University. She beforehand served as Baltimore’s well being commissioner.
NCS: What is polio, and the way is the virus transmitted?
Dr. Leana Wen: Polio, brief for poliomyelitis, is a highly contagious viral disease brought on by the poliovirus. The virus primarily spreads by way of what’s often called the fecal-oral route. That means microscopic particles from an contaminated particular person’s stool can contaminate surfaces, meals or water after which enter one other particular person’s physique by way of the mouth. It can also unfold by way of respiratory droplets when persons are in shut contact.
One problem with polio is that individuals can unfold the virus with out realizing they’re contaminated. Many people have few or no signs however can nonetheless transmit the virus to others.
NCS: What signs does polio trigger, and the way usually does it lead to paralysis?
Wen: Most folks contaminated with poliovirus don’t develop noticeable signs. Roughly 3 out of 4 infections are asymptomatic, in accordance to the CDC.
When signs do happen, they’re usually delicate and may resemble different viral diseases. People could expertise fever, fatigue, headache, nausea, sore throat and muscle aches. These signs often resolve inside a number of days.
In a smaller proportion of instances, the virus impacts the nervous system. Paralytic polio happens when the virus damages motor neurons that management muscular tissues. This can lead to weak spot or paralysis, most frequently affecting the legs. One in 200 infections lead to paralysis, in accordance to the World Health Organization. Among these folks paralyzed, 5% to 10% die when their respiration muscular tissues cease functioning.
NCS: If the United States eradicated polio years in the past, why are vacationers nonetheless being warned about it now?
Wen: The United States eradicated steady transmission of polio in 1979 thanks to widespread vaccination. However, eradication inside a rustic doesn’t remove danger when folks journey to locations the place the virus continues to be circulating. When vacationers go to these areas, they’ll turn into contaminated and convey the virus again with them. That’s why public well being authorities emphasize vaccination earlier than worldwide journey to affected areas.
The danger for any particular person traveler is mostly low if they’re absolutely vaccinated. But from a inhabitants well being perspective, stopping importation is extraordinarily vital. Even a single imported case may lead to native unfold in communities the place vaccination protection is low.
NCS: What international locations are at present seeing poliovirus circulation, and what does the CDC journey alert advise?
Wen: Poliovirus has been detected in 30 international locations, in accordance to the CDC’s journey discover. In addition to international locations in Africa, Asia and the Middle East, the listing additionally encompasses some European international locations, together with Germany, the United Kingdom and Poland.
The CDC makes use of 4 ranges of journey well being notices. Level 1 means follow standard precautions. Level 2, which applies right here, means take enhanced precautions. Level 3 advises vacationers to rethink nonessential journey, and Level 4 recommends avoiding journey altogether.
For the present Level 2 polio discover, the improved precaution is making certain that you’re absolutely vaccinated towards polio earlier than touring. For most individuals, which means finishing the routine childhood series of inactivated polio vaccine. Some folks in particularly high-risk conditions could also be really helpful to obtain one other booster.
NCS: What is the present state of affairs within the United States relating to polio instances or detection?
Wen: The United States doesn’t have ongoing transmission of polio, however public well being officers should stay vigilant.
Health officers recognized a paralytic polio case in 2022 in an unvaccinated grownup in New York. That case, the primary of its form in almost a decade, was vital as a result of it confirmed that poliovirus had been launched into the group. Investigators later detected associated virus in wastewater samples in a number of surrounding counties, indicating that further infections had seemingly occurred with out being acknowledged.
Since then, well being departments have continued monitoring wastewater and vaccination protection. These surveillance programs are designed to detect early indicators of poliovirus, in order that well being officers can reply shortly if wanted.
NCS: Who ought to examine their vaccination standing earlier than touring internationally?
Wen: Anyone planning worldwide journey ought to affirm that they’re up to date on recommended vaccines, together with polio.
Adults who’re uncertain about their vaccination standing ought to evaluate their data or communicate with their well being care supplier. If documentation can’t be discovered, it’s usually protected to obtain the vaccine once more.
Travelers heading to areas the place poliovirus is circulating needs to be significantly cautious to affirm their safety. Travel clinics and first care suppliers may help confirm vaccination data and advise on what further vaccinations could also be wanted.
NCS: Do adults who had been vaccinated in childhood want a booster earlier than touring to areas the place polio is circulating?
Wen: For adults who accomplished the usual childhood vaccination collection, immunity is mostly long-lasting. However, the CDC recommends that some adults touring to areas with elevated danger of polio obtain a single lifetime booster dose of inactivated polio vaccine.
It’s vital to notice that this booster shouldn’t be a part of routine vaccination for the overall inhabitants. This further step is particularly really helpful for individuals who could also be uncovered to the virus by way of journey or sure occupational settings, reminiscent of well being care work. Individuals who should not at excessive danger for occupational publicity however particularly involved about polio might inquire about the booster shot with their main care doctor.
More broadly, the continued presence of polio in elements of the world highlights the significance of world vaccination efforts. Eradicating polio worldwide is the one approach to guarantee it doesn’t return. Until that aim is achieved, sustaining excessive vaccination protection, conducting cautious surveillance and staying alert to travel-related dangers stay crucial instruments for safeguarding public well being.