@josie Seems reasonable. I don’t know enough about infectious disease to argue one way or the other with your statement.
Some of the diseases are still happening in larger numbers in other countries. I recently was reading an article about a measles outbreak in Europe, and someone told me that it’s a strain from Israel. So, I guess there are various strains if that info is correct, I’m not sure if that is from a mutation, or if several strains have existed for a long time.
Usually, when there is an outbreak of measles there are reports of vaccinated people getting it too, but they never say if it’s people with just one shot in the series, or if they are elderly and the immunity might have waned. The efficacy of the measles vaccine is very high, and the way I understood it the different varieties or strains (not sure the correct word) still are covered by the one vaccine because of how closely related they are or something like that. My science is very lacking. Obviously, the vaccine is very effective, because measles is practically unheard of in the US. Especially, before parents in whole communities weren’t vaccinating they’re kids. It’s still extremely rare here, and only because of the vaccine. Measles is crazy contagious.