(05-29-2020, 02:37 PM)Genuine Realist Wrote: I still remember the Salk vaccine on sugar cubes in the early 60's. My dad told me later that the only guy in the country who actually contracted polio lived nearby.
I'll get vaccinated for sure. But maybe I'll squirrel out a cube for BC. Indispensable in my book.
The vaccine on sugar cubes was the oral
Sabin vaccine.
The Sabin live virus vaccine was introduced in 1961. The Salk injectable killed virus vaccine was introduced in 1955. The incidence of polio had already decreased pretty dramatically in the US by 1961 to about 1000 symptomatic cases per year. I think it was 700 in 1962. The Sabin vaccine was much easier to administer and much cheaper, enabling its widespread use throughout the world. 95 to 99% of polio virus infections are asymptomatic. In the early 1950's paralytic polio cases spiked to 21,000 in a single year. Cases were down somewhat by 1955 due to social distancing. I know my parents did not allow us to play with other children during the summer even though we were vaccinated, which was the peak time of transmission for the illness. I was born in 1956.
There are currently 3 countries known to be harboring wild polio virus type 1: Pakistan, Afghanistan, and Nigeria. The military conflicts and social upheaval present in those countries have damaged efforts to finally eradicating the wild type virus. Wild types 2 and 3 have been eradicated.
The Sabin vaccine causes paralytic polio in about 1 or 2 people out of 1 million doses given. There were about 5-8 cases per year in the USA until we stopped using the Sabin vaccine and switched to the Salk about 20 years ago. Worldwide, there are outbreaks of vaccine derived polio every year in countries with lower immunity levels.
https://www.cdc.gov/mmwr/volumes/68/wr/mm6845a4.htm