Poliovirus
In this video, Dr. Roger Seheult of MedCram discusses the recent finding of poliovirus in wastewater in the United Kingdom. It is important to note that wastewater plants routinely check for the DNA or RNA of viruses as a way to monitor for infections. In London, in an area that services about 4 million people, it has come up on the radar that the monitoring time of February to May 2022 saw poliovirus genetic material rates rising. Poliovirus is a single-stranded RNA virus. It is passed on in a fecal-oral manner and particularly has an affinity for the cells in the GI tract. Initial symptoms can include sore throat, tiredness, and fever lasting up to 10 days. It is during this time that due to viral shedding in the GI tract, it can be spread to others. In rare cases, it can lead to muscle weakness and individuals might need to go on a ventilator if respiratory muscles are involved or even develop paralysis in other muscles.
IPV and OPV vaccines
Polio itself has been around for hundreds of years. We rarely encounter polio in the United States due to vaccines. There are two types of vaccines called IPV and OPV. The IPV vaccine is an inactivated injection compared to the OPV vaccine which is an oral and live attenuated vaccine. The OPV vaccine, unlike the IPV vaccine, actually produces antibodies in the blood and GI tract. Taking the OPV vaccine is beneficial in areas where there is a significant amount of person-to-person transmission as having antibodies in the GI tract will prevent further spread; however, this form of the vaccine carries with it a greater risk of developing vaccine-derived poliovirus and vaccine-associated paralytic poliomyelitis.
Polio vaccine use in the United States
The United States has not used the OPV vaccine since 2001 in order to avoid these rare but significant side effects. Once the caseload of poliovirus is low in the general population, it is better to move to use the inactivated vaccine where these side effects do not occur. With the OPV vaccine, there is a rare situation where the poliovirus can mutate and cause an infection. This infection not only can lead to paralysis which is known as vaccine-associated paralytic poliomyelitis but it can also spread to other people and cause disease, vaccine-derived poliovirus, especially in those individuals who are not vaccinated against poliovirus.
In London, thus far only the genetic material from poliovirus has been detected and no actual cases of polio have been reported. Health authorities in Britain, however, have declared this a national incident. In reality, individuals who are immunized against polio do not have to worry too much but those not immunized are cautioned to get vaccinated. The risk for a global pandemic from polio is small but ongoing monitoring is recommended.
LINKS / REFERENCES:
Reported Paralytic Polio Cases and Deaths (Our World in Data) | https://ourworldindata.org/grapher/re…
Vaccine-derived Poliovirus (CDC) | https://www.cdc.gov/vaccines/vpd/poli…
Sabin Vaccine Reversion in the Field (Journal of Virology) | https://www.ncbi.nlm.nih.gov/pmc/arti…
Mutations in VP1 of Poliovirus Specifically Affect Both Encapsidation and Release ofViralRNA (Journal of Virology) | https://journals.asm.org/doi/pdf/10.1…
Britain Declares National Incident After Poliovirus Found in London (NYT) |
https://www.nytimes.com/2022/06/22/he…
Traces of polio virus found in London sewage as health officials declare national incident (Sky News) | https://news.sky.com/story/traces-of-…
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