In 2016, there were only 37 wild cases of polio in the world. Unfortunately, there were 5 vaccine related cases as well. The oral polio vaccine (OPV) is not perfect, but inactivated polio vaccine (IPV) is not effective in an outbreak situation. IPV does not prevent transmission because it isn’t particularly effective in the intestines. So the individual is protected, but the individual will still poop live polio virus if exposed and risk spreading the virus that way. So when an outbreak occurs, in order to offer protection to the uninfected population, OPV is the only option to prevent spreading the disease.
IPV is much more expensive than OPV and is the vaccination of choice in
most countries. IPV is safe and very effective.
Wild cases of polio are still occurring in Afghanistan, Pakistan, and Nigeria. Vaccine-derived cases were reported in Afghanistan, Nigeria, and Laos (hopefully off the list for 2017).
I don’t understand why anyone would take the risk of not getting the IPV if available. The side effects of the vaccine are minimal and mild when they do occur. It offers excellent protection to the vaccinated individual. The probability of importing polio to the USA is low but not negligible, the probability of spreading the virus from feces is low but not negligible (flush a toilet in a shared restroom and the poop from everyone who has ever used that toilet is spewed up in the air, granted in very small amounts), and vaccinated people can spread the disease to unvaccinated people. Even if someone survives polio unscathed, later in life, secondary symptoms often develop. (image from United States Centers for Disease Control).
Happy Birthday to Jonas Salk