In response to the first confirmed case of polio in the United States since 2013 this past September and the subsequent detection of the polio virus in New York City wastewater, officials at the U.S. Centers for Disease Control and Prevention (CDC) are now considering recommending a return to use of the live attenuated oral polio vaccine (OPV), specifically a version known as nOPV2 (novel oral polio vaccine type 2) in the U.S.1 2
The single case of polio, involving a young adult in Rockland County, New York, was detected in July. The individual developed vaccine strain polio paralysis, was temporarily hospitalized, and released.3 4
The U.S. stopped using the OPV in 2000 because it was found that the weakened virus in the vaccine had mutated and was capable of causing what is referred to as “vaccine-derived polio.” In other words, on rare occasions, OPV itself can cause polio in the person vaccinated or in a person who comes in contact with the vaccinated person’s body fluids. It was precisely because of this that in mid-1990s the National Vaccine Information Center (NVIC) called on CDC to discontinue use of the OPV in and replace it with the Salk inactivated polio vaccine (IPV) that cannot cause vaccine strain polio.5 6
More Cases of Polio from OPV Than from Wild Polio
In 2019, the World Health Organization (WHO) published a report confirming nine new cases of polio caused by the OPV in Angola, the Central African Republic, the Congo and Nigeria. The report noted that a total of 16 countries had experienced polio outbreaks caused by the OPV that year, and that more people were contracting polio through continuing use of “live” polio vaccines than from the wild poliovirus itself.7 8
Despite the cases of vaccine-derived polio, on Nov. 13, 2020 the WHO granted an Emergency Use Listing (EUL) to the nOPV2, allowing the vaccine to be distributed for “limited initial use” in countries affected by outbreaks of vaccine-derived poliovirus type 2 (cVDPV2).9
According to the WHO, this EUL process, previously known as Emergency Use Assessment and Listing (EUAL), was created to “assess and list new and yet-to-be licensed vaccines, therapeutics and diagnostics to enable their early, targeted use in response to a Public Health Emergency of International Concern (PHEIC).”9
With regard to recommending use of nOPV2 in the U.S., the CDC’s Janell Routh, MD said:
We are in discussions with our New York State and New York City colleagues about the use of nOPV. It will be a process. It’s not something that we can pull the trigger on and have it appear overnight. There will be lots of thought and discussion about the reintroduction of an oral polio vaccine into the United States.1
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Click here to view References:
1 Kimball S. CDC is discussing using oral polio vaccine for first time in 20 years to stop New York outbreak. CNBC Oct. 21, 2022.
2 Press Release. United States confirmed as country with circulating vaccine-derived poliovirus. U.S. Centers for Disease Control and Prevention Sept. 13, 2022.
3 Cáceres M. Polio Case in New York Caused by “Vaccine-Derived” Poliovirus. The Vaccine Reaction July 24, 2022.
4 Kimball S. How polio came back to New York for the first time in decades, silently spread and left a patient paralyzed. CNBC Oct. 4, 2022.
5 Georgiou A. Is the Polio Vaccine Still Required in U.S. and Why Was OPV Stopped? Newsweek July 22, 2022.
6 Fisher BL, Cáceres M. Polio Eradication Stalls with More Wild-Type and Vaccine Strain Polio Outbreaks. The Vaccine Reaction Dec. 7, 2019.
7 Associated Press. More polio cases now caused by vaccine than by wild virus. Nov. 25, 2019.
8 Meler B. More current polio cases have been caused by vaccines than the wild virus: WHO report. National Post Nov. 26, 2019.
9 Polio Global Eradication Initiative. Novel Oral Polio Vaccine type 2 (nOPV2) granted EUL recommendation. Nov. 13, 2020.