Polio unlikely to spread widely in U.S.

• But experts say the U.S. is highly protected from the widespread transmission of polio, at least in areas that are highly vaccinated.

What they're saying: "If you're an unvaccinated person living in Rockland or Orange County (New York), where sewage is showing there's polio in it, I would be concerned and get vaccinated," Aaron Glatt, infectious disease chief at Mount Sinai South Nassau, told Axios.

• Glatt and several other experts interviewed by Axios said those current on their shots have little reason to be concerned. About 93% of children in the U.S. are vaccinated against polio by their second birthday and received nearly full protection, per the CDC.
• "The good news about this is, if you're vaccinated, you're protected," Patricia Jackson, a spokeswoman for the Association for Professionals in Infection Control and Epidemiology and director of infection prevention White Rock Medical Center in Dallas.

Driving the news: London officials announced plans Wednesday to offer polio boosters to tens of thousands of kids after it was found in wastewater there.

• It comes after CDC officials headed to New York to investigate evidence of transmission of polio in the wastewater in Rockland County after a confirmed case in a 20-year-0ld man. Officials there warned the case was just the "tip of the iceberg" when it came to transmission.
• Officials believe these are all cases originating from vaccines with weakened poliovirus that are not administered in the U.S. but are used internationally, instead of in the wild.
• But they caused transmission in parts of New York that have some of the lowest polio vaccination rates. Rockland also was the site of a measles outbreak in 2018-2019.

Be smart: Polio, last detected in the U.S. in 2013, can lead to paralysis or meningitis, but many people who get the virus in their digestive tract will not display any symptoms at all. Paralysis occurs in an estimated one out of every 200 polio cases, Glatt said.

• There are two forms of the polio vaccine used around the world — the oral polio vaccine with a weakened virus commonly used in the developing world and the inactivated polio vaccine, which has been the only shot given in the U.S. since 2000.
• That shift occurred because of the small risk that the weakened virus could mutate and take on characteristics of naturally occurring polio, then potentially spread to those who are unvaccinated, William Schaffner, professor of infectious diseases at Vanderbilt University, told Axios.

• "There are possibly other cases that haven't been diagnosed, but I think it's good news we don't have a lot of diagnoses and people are starting to think about it," Glatt said of the one currently confirmed case in New York.

Between the lines: Wastewater surveillance has been used to survey for polio in the past, and this strategy, widely adopted during the COVID pandemic, has become a standard public health tool.

• Samples of wastewater can't pinpoint individual cases but can give a clue about regional health threats. The surveillance has also been used in places like San Francisco to track monkeypox.
• Experts believe wastewater surveillance can be successfully deployed to track antibiotic-resistant superbugs, among other threats.

The big picture: The simultaneous outbreaks of highly virulent, potentially deadly diseases could become a disturbingly familiar pattern.

• The public is both more acutely aware of these threats and able to more closely monitor the transmission after COVID, Schaffner said.
• Increased vaccine hesitancy, historic levels of global travel and more human contact with insects and animals that harbor virus are likely to keep driving the trend, he said.
• "There are many of us living in the United States who have a very locally-focused point of view. We don't much care about what's going on over there," Schaffner said.
• "The fallacy of that is: Whatever is over there can be over here in 12 to 24 hours. And it can spread," he said. "We have to work internationally."