Measles has an R0 of 12-18, so 1 case can spread to 12-18 new cases in a non-immune population. Measles vaccines are "live virus" types, where the virus must be active but weakened, to cause a very mild infection. This is a fine line to walk. Some batches may be "hot" and cause actual measles, particularly in immunosuppressed people. Other batches may be too attenuated and fail to "take", so the recipient is not immune to measles.
All of this stage is already set, and there are no really good treatments for measles, though vitamin-D levels support immune function, vitamin-A helps in many cases, and zinc may help. Nothing is like a "cure".
So vaccine-religions of both sorts need to be set aside during an outbreak, where a lot of people might not have effective immunity, and only the never-vaccinated realize it.
From Dr. John Day
Measles outbreaks are an awkward special case, as the measles case fatality rate in WW-1 era soldiers was around 12%, but around 0.1% in children. https://jmvh.org/article/measles-mortality-in-the-armies-of-the-early-20th-century/
Measles has an R0 of 12-18, so 1 case can spread to 12-18 new cases in a non-immune population. Measles vaccines are "live virus" types, where the virus must be active but weakened, to cause a very mild infection. This is a fine line to walk. Some batches may be "hot" and cause actual measles, particularly in immunosuppressed people. Other batches may be too attenuated and fail to "take", so the recipient is not immune to measles.
All of this stage is already set, and there are no really good treatments for measles, though vitamin-D levels support immune function, vitamin-A helps in many cases, and zinc may help. Nothing is like a "cure".
So vaccine-religions of both sorts need to be set aside during an outbreak, where a lot of people might not have effective immunity, and only the never-vaccinated realize it.