Thank you very much for this post! I was a child then and I remember hearing about it at the time, but never learned the full story.
My pleasure! I'm a little embarrassed that I got the model of plane wrong, as I did this all from memory, and I was a kid then.
So I looked it up and got this nice concise summary from the web site of the Smithsonian's David J. Senser Museum of the CDC (Centers for Disease Control) about their epidemiological investigation at the time -- this had become a really big deal for the freakin' CDC to get involved! And when the CDC solved it, it became a memorable enough event that they kept some artifacts from the investigation to display in the CDC Museum! (Photo at the link.)
Apparently the CDC spent the first 3 months of 1980 on the investigation. Some of the details are interesting (fair use from the web site):
"Airline personnel had investigated the ventilation systems, cleaning materials and procedures, concluding all were normal. Chemical tests on clinical specimens for the presence of blood were negative.
Bacteriological tests were negative. Review of 132 cases occurring in January and February:
96% occurred on flights between New York and Miami.
90% occurred on a single type of aircraft.
91 flight attendants had been affected."
It's interesting that 90 percent of the reported
cases occurred on the A300, when the cause (i.e. 100 percent) was found to be things only on that aircraft. Delusions/rumours at the MIA crew base? People wanting to join in with "it happened to me, too!"?
My memory was pretty-good on the cause and the psychosomatic symptoms. The CDC says: "Observations of standard work practices and procedures of flight attendants revealed that the red spots were caused by red ink flaking off the life vests. The vests used for demonstrations were not actually functional and were labelled “Demo Only” with ink containing a litholrubine chrome molybdate orange pigment. When the vests were demonstrated, the red ink areas came into close contact with the face, necks, and hands of the demonstrators. Although some reports mentioned burning, nausea, and headache in association with spots, most reports involved only the occurrence of bright red spots that could be wiped or washed off. When the implicated vests were removed from all Eastern Airlines planes, the epidemic ended."https://www.cdc.gov/museum/history/redspots.html