Polio spread is being monitored by healthcare officials in the United States, with one case of polio-prompted paralysis having been confirmed in New York state.
Healthcare experts say global outbreaks of vaccine-derived polio cases should prompt parents to vaccinate their children as soon as possible, and adults to ensure they're up-to-date on their polio vaccines.
If you're traveling internationally, experts add that a polio booster shot may be necessary depending on your destination.
Once known to paralyze thousands of children each year, poliomyelitis — otherwise known as polio — has been recently detected in New York state, as well as abroad in London and Jerusalem, prompting new warnings from health officials around the globe. According to reports issued by Reuters, it's the first time that the potentially deadly disease may be quietly spreading in the United States in over 20 years.
While polio spread freely largely through asymptomatic cases in the 20th century, recent detections have indicated that the virus sourced in New York and abroad is what's known as vaccine-derived polio, explains Peter F. Wright, M.D., infectious disease and international health practitioner for New Hampshire-based Dartmouth Health. This kind of spread often occurs when an oral vaccine is in use, containing live (albeit weakened) poliovirus; those vaccinated introduce the virus into wastewater in the weeks after their vaccination, which may mutate and then impact under-vaccinated communities where there is low immunity. U.S. health officials no longer use live polio vaccines due to this risk, Dr. Wright adds.
After a case of paralytic polio was found in Rockland County, wastewater surveillance has been used as a tool for health officials to assess the spread of the virus in communities. But New Yorkers should know that wastewater is *not* the same as drinking water. ⬇️ pic.twitter.com/sSeUAWPwNk
— NYSDOH (@HealthNYGov) August 18, 2022
So far, there's been just one case of paralysis reported in New York — but the same form of polio has been known to trigger outbreaks across the globe, including 415 cases of infection in Nigeria last year, per Reuters. Afghanistan and Pakistan are among the only nations where polio spread remains uncontrolled.
There isn't a cure for polio, but current vaccinations provide an overwhelming amount of protection that renders serious polio infections very unlikely — which is why anyone who has been vaccinated in their lifetime shouldn't worry too much.
"Those who have received all of their childhood vaccinations, and children who are up-to-date on their routine vaccinations, don't need to worry about contracting paralytic polio — or seek a booster vaccine," says Shira Doron, M.D., infectious disease physician and hospital epidemiologist at Tufts Medical Center.
"The routine childhood vaccination regimen in the U.S. consists of 4 doses of an inactivated polio vaccine… three doses are considered 99 to 100% effective against paralytic polio," she adds.
Health officials are instead focusing on those who have yet to be vaccinated, encouraging parents to catch up on getting their children vaccinated if they have yet to do so; COVID-19 pandemic disruptions to healthcare have resulted in an immunization gap for many families, according to data highlighted by the United Nations.
When was the polio vaccine released?
Dr. Wright tells Good Housekeeping that U.S. doctors first began administering the earliest versions of polio vaccines in the 1950s and 1960s. "They were very successful in eliminating polio from the United States; there are now currently two types of polio vaccines available, but the vaccine that is used in the U.S. is inactivated polio vaccine, or IPV," he adds. "It stimulates very good antibodies in the blood, and in doing that, is protective against the neurologic disease known as poliomyelitis."
According to information highlighted by the Centers for Disease Control and Prevention (CDC), IPVs became the sole option for vaccination in the U.S. healthcare system in 2000; it has largely blocked any risk of vaccine-derived polio spread domestically since.
Vaccine-derived polio spread remains a risk to unvaccinated Americans, however, because an overwhelming majority of international communities don't have access to IPVs — meaning they continue to rely on oral polio vaccinations, which can cause wastewater contamination that healthcare professionals are currently tracing in major cities. This is likely how the recent spread in New York state first began, as reported by Scientific American.
How long does the polio vaccine last?
Depending on the laws in your state, children are generally required to receive polio vaccinations in staggered doses as they age; the CDC currently recommends a three-dose series for babies and a fourth booster shot between four and six years of age. If you've received a four-dose IPV series as a child, you're still well-protected against polio; two doses of IPV reduce the risk of serious infections by 90%, whereas three doses provide an overwhelming 99% reduction overall.
The 1st case of paralytic #polio in the US in almost 10 yrs in an unvaccinated adult & poliovirus in wastewater in NY are an urgent reminder of importance of vaccination. Those not fully vaccinated against polio are at risk for infection & paralysis. More: https://t.co/BFBwv1wkkb pic.twitter.com/pVUo5auCeA
— CDC (@CDCgov) August 16, 2022
"The best and only public action necessary at this moment is to make sure that you and everyone in your family are up-to-date on childhood polio immunizations," Dr. Doron says. "Vaccine campaigns are underway in New York, where vaccination rates for polio have sadly been found to be inadequate to prevent an outbreak."
Here's why: While vaccinations protect individuals from serious infections and side effects (paralysis included!), they do not exclusively prevent infection risk from vaccine-derived polio that may circulate among communities — which can then lead to outbreaks among those who haven't received a polio vaccine.
"Serum antibody levels in virtually everybody in the U.S. who have been vaccinated are readily detected, and highly protected against getting any of the neurologic disease, despite being somewhat susceptible to spreading the infection to others… [however] they will be very well protected, virtually 100%," adds Dr. Wright.
Do I need to get a polio vaccine booster?
Childhood vaccinations are often adequate to provide prime protection against infection for decades, but you may hear some chatter about polio booster shots as more information is made available. Booster shots aren't unheard of when it comes to polio vaccines, but the likelihood is that you won't be needing one anytime soon.
According to Dr. Doron, those facing three specific situations should talk to their doctor about receiving additional polio vaccines:
Adults who are traveling internationally or to a region of the world experiencing high rates of polio
Adults who work in medical labs handling specimens that may contain poliovirus
Adult healthcare workers who may be likely to take care of polio patients
Currently, state and federal healthcare officials are working to learn more about the spread of vaccine-derived polio in New York and any other affected states. New recommendations may arrive in the future based on their findings, explains Dr. Wright.
"Your only reason to consider getting a booster at this point is if you're uncertain about being vaccinated, or in the case that you are in a group or a household that has been hesitant about getting vaccinated previously," he adds.
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