The Centers for Disease Control and Prevention is considering using an oral polio vaccine for the first time in more than 20 years to stop an outbreak in the greater New York metropolitan area that left an adult paralyzed over the summer.
“We are in discussions with our colleagues in New York State and New York about the use of nOPV,” said Dr. Janelle Root, head of the CDC’s domestic polio team, referring to the new oral polio vaccine. The oral vaccine the CDC is considering is a newer form that is more stable and carries less risk of mutation.
“It will be a process. It’s not something we can pull the trigger and make it happen overnight,” Root told CNBC on Friday. “There will be a lot of thought and discussion about reintroducing oral polio vaccine in the United States,” she said.
The New York State Department of Health said in a statement that it is collaborating with the CDC on potential future options for responding to the outbreak.
US drug regulators pulled the oral vaccine off the shelves in 2000 because it contains a live, but weakened, strain of the virus that can, in rare cases, mutate into a virulent form that is contagious and can potentially paralyze unvaccinated people .
Scientists believe this latest outbreak was caused by someone who was vaccinated with the live virus overseas and started a chain of transmission that eventually found its way to the United States. The sewage samples in New York are linked to earlier samples in London and Jerusalem. It is not clear where the original transmission began.
While the oral vaccine doesn’t usually cause polio that paralyzes people, this one did because it was able to mutate into more virulent strains as it spread among unvaccinated people.
The US currently uses an inactivated polio vaccine, which is given as an injection and contains a chemically killed virus that cannot replicate, mutate or cause disease. Although New York State health officials began an immunization campaign with inactivated polio vaccines, this vaccine did not stop this outbreak.
The CDC has established a task force within its Committee of Independent Vaccine Advisors to develop criteria for when the new oral polio vaccine may need to be used to stop the current outbreak in the New York area and potential future ones. The task force met publicly for the first time on Wednesday and includes experts from New York.
“Since this epidemic occurred in New York, it was decided that we should revisit polio. It really is that simple,” said Dr. Oliver Brooks, chair of the task force and chief medical officer at Watts Healthcare in Los Angeles.
The problem is that although the inactivated vaccine is very effective at preventing paralysis, it does not stop the transmission of the virus. The oral polio vaccine is much more effective at stopping the transmission of the virus and is commonly used to suppress outbreaks.
The strain of poliovirus currently circulating in the New York metro area has mutated and is genetically related to the Sabin type 2 strain used in an older version of the oral polio vaccine.
The US, if necessary, would use the new oral polio vaccine, which is safer, and a newer version that is more stable and carries a much lower risk of mutating into a viral strain that can spread and cause disease in people who are not vaccinated, according to Ruth.
The new oral polio vaccine was developed to stop poliovirus outbreaks caused by the less stable, older version of the vaccine, according to the Global Polio Eradication Initiative. More than 450 million doses have been administered in 21 countries worldwide.
Any decision to use the new oral polio vaccine will require either approval or emergency use authorization from the Food and Drug Administration. CNBC has reached out to the FDA for comment.
Raut, during the CDC advisors meeting on Wednesday, said the goal of the public health response is to prevent additional cases of paralysis, but also to eliminate the circulation of the virus in the wastewater.
“While we have detections in sewage of this circulating virus linked back to the patient’s virus, we know that there is ongoing transmission in the community even without paralysis,” Root said.
The World Health Organization is recommending that countries using the inactivated vaccine, such as the United States, consider introducing the new oral polio vaccine if the inactivated vaccines do not stop the outbreak.
“If we start to see this virus get out of its current geography and population, I think that’s when we have to start thinking about other methods,” Ruth said during Wednesday’s meeting.
An unvaccinated adult in Rockland County, New York, was paralyzed in June after contracting poliovirus. It was the first known case in the US in nearly a decade and the first in New York since 1990. So far, there have been no other cases of paralysis, although New York state health officials have warned that unvaccinated people are at serious risk and should get their shots up to date immediately.
CDC considers one case of paralytic polio a public health emergency. Most people infected with polio do not show symptoms, so when someone is paralyzed, it is an indication that the virus is spreading widely and silently.
The New York State Department of Health has found poliovirus in sewage since April and as recently as September in several counties in the New York area. The virus was found in 70 samples of sewage in Rockland, Sullivan, Orange, Nassau, Kings and Queens counties.
The US was declared polio-free in 1979.
New York Governor Kathy Hochul declared a state of emergency in September, and Health Commissioner Dr. Mary Bassett declared the spread of polio an immediate public health threat.
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