Measles, mumps, and rubella (MMR) vaccines do not and never did contain thimerosal (Mercury). Varicella (chickenpox), inactivated polio (IPV), and pneumococcal conjugate vaccines have also never contained thimerosal.(mercury )
Flu vaccines contained thimerosal. The reason MMR and Chicken pox vaccines did not have mercury is because they were supplied in single use vials because and consequently did not need thimerosal.
The whole mercury in vaccines causes autism has been debunked. But regardless measles, mumps, and rubella all are far more dangerous to kids than COVID is. Plus unlike Covid vaccine which does not prevent transmission the MMR vaccine is actually 97% effective at stopping transmission of MMR.