With a single case of paralytic polio detected in Rockland County, New York, and the virus appearing in sewage samples in two counties in the state, as well as New York, health officials say that poliomyelitis is probably circulating undetected.
This is a particular danger for unvaccinated communities, as poliomyelitis can sometimes cause severe symptoms, including meningitis, permanent paralysis and even death.
“For every case of paralytic polio identified, hundreds more may go undetected,” New York City Health Commissioner Dr. Mary Bassett said in a statement earlier this month. “The best way to keep adults and children polio-free is through safe and effective vaccination.”
The Centers for Disease Control and Prevention recommends that children receive four doses of the polio vaccine with one dose each given at 2 months of age; 4 months; between 6 months and 18 months; and between 4 and 6 years old.
Currently, each state and the District of Columbia requires that children enrolled in kindergarten have received at least three doses or all four doses of the vaccine.
Although CDC data shows that nearly 94% of kindergarten students in the United States received the polio vaccine for the 2020-2021 school year, rates vary by state.
Data shows that Mississippi has the highest rate in the nation with 98.9% of kindergarteners vaccinated against polio.
Louisiana rounds out the top five; New York, excluding New York; Nebraska; and Rhode Island.
Meanwhile, Washington, DC has the lowest rate with just 80.4% of students vaccinated before the school year.
Idaho has the second lowest rate at 86.6%, followed by Wisconsin, Hawaii and Georgia, all with rates below 90%.
“What you need for epidemics to start and persist in our population is where people are not optimally vaccinated, where there are a lot of unvaccinated people,” said Dr Adam Ratner. , director of pediatric infectious diseases at NYU Langone Health, told ABC News. . “And it doesn’t have to be at a country or state or even county level. It can be small pockets of people who can’t handle an outbreak and sustain it.”
Many factors contribute to low vaccination rates, experts told ABC News, but one of the biggest factors is the COVID-19 pandemic.
They explained that because parents did not take their children to routine appointments, vaccinations were missed and because children were not physically in the classrooms, the application of the vaccinations required to go to the school had become lax.
“Primary health care has been globally disrupted,” Dr. Walter Orenstein, associate director of the Emory Vaccine Center, told ABC News. “Since many children are vaccinated through primary health care, they don’t come to visits. If it’s more telemedicine, you lose opportunities to vaccinate.”
Between 1951 and 1954, an average of 16,000 cases of paralytic polio and 1,800 polio deaths were reported each year, according to the CDC. In 1955, the first polio vaccine became widely available.
Cases have slowly gone from less than 1,000 per year to less than 100 per year. In 1994, poliomyelitis was declared eliminated in the Americas.
Experts say that because the disease is so rarely seen, people don’t remember a time when polio was rampant.
“A lot of people have never seen a case of polio because we had, until this recent introduction, eliminated polio in the United States and much of the world,” Orenstein said. “And these are terrible diseases and vaccines are so good at preventing them.”
Exemptions are likely another reason behind the low rates, experts said.
All 50 states allow children to be exempted from vaccination for medical reasons, such as an allergy to a component of the vaccine or a weakened immune system that would make the vaccine harmful.
However, some states allow non-medical exemptions, including religious beliefs or philosophical and personal convictions.
In Idaho, 8.2% of kindergarten students were exempt from one or more vaccines for the 2020-2021 school year, mostly for non-medical reasons. Similarly, 5.2% of kindergarten children in Wisconsin were exempt from one or more vaccines, according to CDC data.
However, in Mississippi, exemptions for “religious, philosophical, or conscientious reasons” are not permitted by state law, according to the Mississippi State Department of Health.
That means only 0.1% of kindergarteners in Mississippi received exemptions for one or more vaccines last year, and only for medical reasons, according to CDC data.
Similarly, New York State eliminated non-medical exemptions for mandatory school vaccinations, including the polio vaccine.
As a result, the Empire State also only had 0.1% of kindergarten students in the state who were medically exempt, according to CDC data.
“The data clearly shows that the more rigorous the school laws are in their enforcement, the higher the vaccination coverage,” Orenstein said.
To improve those rates, experts said communities need to be educated about the safety and effectiveness of vaccines.
“We need to find people who the hesitants trust and who could be messengers to educate them about the safety and effectiveness of vaccines, the enormous rigor with which a vaccine is produced and evaluated before it is licensed. and available, the continuous monitoring system for safety and effectiveness,” said Orenstein.
Ratner said public health departments can also target communities with lower vaccination rates to combat misinformation and understand why people are hesitant to get vaccinated.
“The things we vaccinate against are, without exception, dangerous diseases,” he said. “These are real dangerous diseases that haven’t gone away. If you think about polio, which hasn’t been on people’s minds in the United States for a long time, because we haven’t had a case of polio here for a long time and it’s great. But the reason we haven’t had polio here is because we vaccinate our children.”
Ratner said it was frustrating to hear that polio was being detected again.
“And children who are under-vaccinated, and there are many of them, are really, really at risk for paralytic poliomyelitis,” he added. “And it’s sad and frustrating to deal with kids who have things that we can prevent.”