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 advisable that vacationers to affected nations 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 threat when the virus is circulating elsewhere. Because poliovirus spreads simply and may transfer throughout borders via 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 crucial? Which elements of the world are seeing poliovirus circulation now? Should vacationers verify 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 CNN wellness professional 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.
CNN: What is polio, and the way is the virus transmitted?
Dr. Leana Wen: Polio, brief for poliomyelitis, is a highly contagious viral disease attributable to the poliovirus. The virus primarily spreads via what’s generally known as the fecal-oral route. That means microscopic particles from an contaminated individual’s stool can contaminate surfaces, meals or water after which enter one other individual’s physique via the mouth. It can also unfold via respiratory droplets when individuals are in shut contact.
One problem with polio is that folks 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.
CNN: What signs does polio trigger, and the way typically does it lead to paralysis?
Wen: Most individuals 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 typically gentle and may resemble different viral sicknesses. People could expertise fever, fatigue, headache, nausea, sore throat and muscle aches. These signs often resolve inside a couple of days.
In a smaller share of instances, the virus impacts the nervous system. Paralytic polio happens when the virus damages motor neurons that management muscle tissue. This can lead to weak point or paralysis, most frequently affecting the legs. One in 200 infections lead to paralysis, in accordance to the World Health Organization. Among these individuals paralyzed, 5% to 10% die when their respiration muscle tissue cease functioning.
CNN: 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 threat when individuals journey to locations the place the virus remains to be circulating. When vacationers go to these areas, they will grow to be contaminated and produce the virus again with them. That’s why public well being authorities emphasize vaccination earlier than worldwide journey to affected areas.
The threat for any particular person traveler is mostly low if they’re absolutely vaccinated. But from a inhabitants well being perspective, stopping importation is extraordinarily necessary. Even a single imported case could lead on to native unfold in communities the place vaccination protection is low.
CNN: What nations are at the moment seeing poliovirus circulation, and what does the CDC journey alert advise?
Wen: Poliovirus has been detected in 30 nations, in accordance to the CDC’s journey discover. In addition to nations in Africa, Asia and the Middle East, the record additionally encompasses some European nations, together with Germany, the United Kingdom and Poland.
The CDC makes use of 4 ranges of journey well being notices. Level 1 means observe common 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, meaning finishing the routine childhood series of inactivated polio vaccine. Some individuals in particularly high-risk conditions could also be advisable to obtain one other booster.
CNN: What is the present state of affairs within the United States concerning 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 sort in practically a decade, was important as a result of it confirmed that poliovirus had been launched into the neighborhood. 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 rapidly if wanted.
CNN: Who ought to verify 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 assessment their information or communicate with their well being care supplier. If documentation can’t be discovered, it’s typically protected to obtain the vaccine once more.
Travelers heading to areas the place poliovirus is circulating must be significantly cautious to affirm their safety. Travel clinics and first care suppliers can assist confirm vaccination information and advise on what further vaccinations could also be wanted.
CNN: 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 threat of polio obtain a single lifetime booster dose of inactivated polio vaccine.
It’s necessary to be aware that this booster isn’t a part of routine vaccination for the final inhabitants. This further step is particularly advisable for individuals who could also be uncovered to the virus via journey or sure occupational settings, corresponding to well being care work. Individuals who usually are not at excessive threat for occupational publicity however particularly involved about polio might inquire about the booster shot with their major care doctor.
More broadly, the continued presence of polio in elements of the world highlights the significance of worldwide vaccination efforts. Eradicating polio worldwide is the one manner to guarantee it doesn’t return. Until that purpose is achieved, sustaining excessive vaccination protection, conducting cautious surveillance and staying alert to travel-related dangers stay important instruments for safeguarding public well being.
