By Dennis Thompson
Health Day Reporter
MONDAY, August 15, 2022 (HealthDay News) — The poliovirus detected in New York City wastewater last week alerted public health officials, as it indicated the potentially disabling virus was circulating widely in the area.
But infectious disease experts say there’s no need for families of fully vaccinated children to panic.
“The inactivated polio vaccine is part of the standard childhood immunization schedule, so for most families, it’s not a cause for concern,” says Dr. Gail Shust, pediatric infectious disease specialist at NYU Langone Hassenfeld Children’s Hospital in New York City. . “It just so happens to be a very effective vaccine.”
At this point, there is also no need to look for polio boosters for fully vaccinated children or adults, he added.
“For children who are already on the normal vaccination schedule in the United States, there is no reason for them to get a booster,” Shust said.
Instead, attention should be focused on communities with groups of unvaccinated children and adults, as these are the people who are at risk of contracting polio, experts say.
A young man in Rockland County, NY — about 45 minutes northwest of the Bronx — was diagnosed in late July with the first identified case of paralytic polio in the United States in nearly a decade.
Subsequently, poliovirus was detected in the wastes of nearby Rockland County and Orange County, indicating community transmission of the virus.
Polio can cause permanent paralysis of the arms and legs. It can also be fatal if there is paralysis of the muscles used for breathing or swallowing.
About 1 in 25 people infected with the poliovirus will develop viral meningitis, and about 1 in 200 become paralyzed.
“A lot of people are infected with the polio virus, they are asymptomatic,” Shust said. “It’s very possible there are other cases that haven’t been diagnosed and there are more people infected than we realise.”
Children should receive at least three doses of the polio vaccine by 18 months of age, with a fourth dose given between ages 4 and 6, according to the US Centers for Disease Control and Prevention.
New York state health officials said they were particularly concerned about an environment where less than 70% of children between the ages of 6 months and 5 years had received at least three doses of the polio vaccine.
About 86% of New York City children get all three doses, but in Rockland County it’s just over 60%, and in Orange County it’s just under 59%, state health officials said.
Statewide, nearly 79% of children had received three doses by their second birthday, officials said.
The polio virus has also been identified in London wastewater, and health officials in the UK have decided to offer a booster polio vaccine to children.
“They started doing that in London. We haven’t said it’s necessary,” said Dr. William Schaffner, medical director of the National Foundation for Infectious Diseases based in Bethesda, Md.
“The only time we’ve given a booster in the past was when someone who was vaccinated as a child then decided to travel to some developing country where there’s a lot of polio, and we said, OK, just in case, to be careful. careful, we’ll give you a push before you leave,” said Schaffner. “It wasn’t really deemed necessary, but it was a wise, extra, easy and safe thing to do.”
The poliovirus lives in the intestinal tract and can be transmitted through feces, so wastewater surveillance is a logical way to track it, said Vincent Racaniello, professor of microbiology and immunology at Columbia University in New York City.
“This virus has probably been in the sewers for years,” he said. “We never looked for them, and now we’re starting to look because of this case. And I would say the more we search, we’ll find them all over the US, especially in big cities.”
This strain of poliovirus likely entered the United States from people in other countries who had received the oral polio vaccine, Racaniello and Schaffner said.
The oral vaccine was the first to be developed and the easiest to administer, so it is still being used as part of the World Health Organization’s polio eradication efforts worldwide, experts say. But, says Racaniello, it’s an infectious vaccine, meaning it contains an attenuated version of the virus itself.
“It multiplies in your gut, and you release it — that’s the virus in the feces. It spreads very easily, and it can cause polio even though it’s a vaccine virus. Once it passes through the human gut, it can regain the ability to cause polio.”
The United States stopped using the oral vaccine in 2000, after the US Preventive Services Task Force decided that the risk of some accidental cases of polio was too great, Schaffner said.
“Every year we have about 4 million births and we have between six and 10 cases of vaccine-related poliomyelitis,” he said. “We deliver small numbers of paralyzed children and adults by using oral vaccines.”
The US now uses exclusively the inactivated four-dose polio vaccine.
“The virus is dead. It’s impossible to double. It cannot mutate. It can’t cause paralysis,” said Schaffner. “But as an inactivated viral vaccine, it has to be given by syringe, which is more complicated and much more expensive and, of course, increases the number of inoculations young children get. , which doesn’t make mom too happy.”
Schaffner said it was “important” that vaccine-associated poliovirus circulated in the United States.
“We didn’t expect it to be widespread, so we just found there was more intercontinental transmission of this oral polio vaccine virus than we thought,” said Schaffner.
“If you had asked me before this case, I would have said that unless someone has recently gone abroad or has visitors from overseas, you won’t find them here because we don’t use [the oral vaccine] in the United States,” added Schaffner. “But we may be a smaller global community than I thought.”
The only true protection is vaccination, and Racaniello hopes that the wastewater surveillance data will help convince those who have doubts about vaccines to go ahead and get their shots.
“Maybe they thought there was no polio virus in the US, right? So they said I didn’t need to be vaccinated,” Racaniello said. “So now we can show them it’s there. In fact, I think we should do more wastewater control and show people, look, it’s in every major metropolis. You’d better get vaccinated.”
The US Centers for Disease Control and Prevention has more on polio.
SOURCES: Gail Shust, MD, pediatric infectious disease specialist, NYU Langone Hassenfeld Children’s Hospital, New York City; William Schaffner, MD, medical director, National Foundation for Infectious Diseases, Bethesda, Md.; Vincent Racaniello, PhD, Higgins Professor, Department of Microbiology and Immunology, Columbia University, New York City