The MMR vaccine does not contain Mercury. The MMR vaccine has never contained mercury. No vaccine has ever contained Mercury. Some vaccines, those that came in multi-dose vials, had an additive to prevent microbial growth. That additive was ethylmercury, or thimerosal/thiomersal. To suggest that ethylmercury might cause mercury poisoning is the same as suggesting that common salt, sodium chloride, might cause chlorine poisoning. It confuses an element with a chemical compound.
The paper you reference, on the possible link between arthritic disease and those people who have received a vaccine also points out that those women are at more risk were they to contract the virus itself; Further, it draws several conclusions.
1."Even these 'frequent' associations relate to a relatively small number of patients. Whenever controlled studies of autoimmunity following viral vaccines were undertaken, no evidence of an association was found."
and
2."Very few patients may develop some autoimmune diseases following viral vaccination (in particular - arthropathy, vasculitis, neurological dysfunction and thrombocytopenia). For the overwhelming majority of people, vaccines are safe and no evidence linking viral vaccines with type 1 diabetes, multiple sclerosis (MS) or inflammatory bowel disease can be found."
True, the Urabe strain was used as the Measles component of the MMR until around 1992, when the evidence pointed to a link between that component and a mild, transient viral meningitis - and as soon as that link was demonstrated, a different strain was used, which has gone on to show no problems at all.
Medical science works on evidence of harm. The surveillance system for vaccines is pretty good.If it were only your kids that were being left at risk of developing measles, thats one thing - but by choosing not to vaccinate you are also putting the children of others at risk.
For myself, I believe your calculation of relative harms is wrong, and you downplay the severity and possible harms and consequences of those very childhood diseases that vaccinations are there to prevent.