The New Polio Outbreak Is Bad. But Why Hasn't It Become a Disaster (Yet)?https://doctorbuzz.substack.com/p/the-new-polio-outbreak-is-bad-butInteresting Polio Vaccine Fact #1: The Salk vaccine, generally known as the inactivated polio vaccine (IPV), developed first and used exclusively in the US since 2000, is incredibly effective (99%+) at preventing paralytic poliomyelitis but does not convey mucosal immunity, and therefore does little to reduce transmission of the poliovirus.
Yes, a true life-saving, disability-sparing vaccine, and one with virtually no adverse effects. However, the inactivated virus triggers a marvelous immune response in the blood without establishing immunity in the gut. Since poliovirus is a fecal-oral route pathogen — meaning viral particles are not passed in tiny aerosols from our breath, or large droplets from a cough, but rather in tiny bits of fecal matter that make their way onto hands, or into the water supply, and then into mouths — the poliovirus can readily spread itself in its usual manner among a population entirely immunized via the IPV vaccine. ...
...
Interesting Polio Vaccine Fact #2: The live attenuated Oral Polio Vaccine, developed by Dr. Albert Sabin, is cheap, easy (taken as a few drops of liquid by mouth), and remarkably effective both at preventing infection in the gut as well as severe neurological disease, but has an Achilles heel: it can mutate back into a virulent form of polio!
This is the vaccine that has virtually eliminated wild-type polio from the globe. In the US, it was used exclusively for decades until polio was essentially gone, and then IPV reintroduced. Why bring back the older, more expensive IPV? The faint risk of vaccine-associated paralytic polio (VAPP). Very rarely — in the 1 in 2-3 million range — people who receive the vaccine, often immune-compromised, brew up a case of paralyzing poliomyelitis if the virus mutates into a pathogenic form and attacks the nervous system. Sometimes, too, especially in communities employing the OPV vaccine but with lower rates of acceptance, a strain could circulate among the community and acquire mutations over a year or two that would revert it back to a pathogenic strain, so-called “circulating vaccine-derived poliovirus” (cVDPV). The treatment, at least until 2020, was to give everybody more OPV until herd immunity is built up and hope to avoid more vaccine-associated or vaccine-derived cases of polio!
1. This, obviously, bears on current events in the London and NYC areas.
2. If, like me, you received the liquid vaccine soaked into a sugar cube, you probably received the Sabin Oral Polio Vaccine.
3. Neither vaccine utterly prevent initial infection by some form of a polio virus. "Immunity" is a misleading word, an over-simplification. What both prevent - with very high, though not perfect, success - is the virus attacking the CNC and causing paralysis.
