What’s in the MMR vaccine? © Getty Images

What’s in the MMR vaccine?

To make a vaccine just add water, a dash of virus and some ingredients to help keep it alive.

The active ingredient of vaccines can vary dramatically – they might take the form of live (but weakened) viruses, completely inactivated viruses or just fragments of a virus or bacteria. There are numerous ways the vaccine might be administered, for example, orally, nasally or by a jab. These factors require different components to make the vaccine easy to produce, effective and stable. Let’s take a single dose of a measles, mumps and rubella jab as an example.

© Raja Lockey
© Raja Lockey

Water: 464.4mg (93.47 per cent)

Live virus particles: About 0.003mg (0.0006 per cent). The smallest component of the vaccine are the weakened measles, mumps and rubella viruses.

Hydrolysed gelatin: 15mg (3 per cent). A stabiliser that protects the viruses from the effects of changing temperatures during preparation and storage.

Sodium phosphate: 0.3mg (0.06 per cent). This keeps the whole thing at a pH that the viruses need to stay alive.

Recombinant human albumin: about 0.3mg (0.06 per cent). Another stabiliser made by bacteria engineered to produce a human protein.

Sucrose: 2mg (0.4 per cent). Yet another stabiliser!

Sorbitol: 15mg (3 per cent). This is more commonly used as an artificial sweetener. Here, it acts as another stabiliser.


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