Well, maybe. If you imagine that every trivalent vaccine (measles-mumps-rubella) ever given in the whole world was created, licensed, and manufactured by Merck, then yes. If you understand that (more or less) 196 countries in the world may each have differing formulations for trivalent measles-mumps-rubella vaccine, then no.
Examples of trivalent measles-mumps-rubella not manufactured by Merck:
- Immravax MMR vaccine, manufactured by Sanofi Aventis, Measles (Schwarz Strain), Mumps (Urabe AM 9 Strain), Rubella (Wistar RA 27 / 3 Strain)
- Priorix MMR vaccine, manufactured by GlaxoSmithKline (attenuated Schwarz measles, RIT 4385 mumps (derived from Jeryl Lynn strain) and Wistar RA 27/3 rubella strains of viruses)