Защото знам че няма да си направиш труда да го прочетеш както ти посочих да схвянеш за какво става въпрос и защо се използват ето ти обяснението тук:
Excipients
Beside the active vaccine itself, the following excipients are commonly present in vaccine preparations:[33]
* Aluminum salts or gels are added as adjuvants. Adjuvants are added to promote an earlier, more potent response, and more persistent immune response to the vaccine; they allow for a lower vaccine dosage.
* Antibiotics are added to some vaccines to prevent the growth of bacteria during production and storage of the vaccine.
* Egg protein is present in influenza and yellow fever vaccines as they are prepared using chicken eggs. Other proteins may be present.
* Formaldehyde is used to inactivate bacterial products for toxoid vaccines. Formaldehyde is also used to kill unwanted viruses and bacteria that might contaminate the vaccine during production.
* Monosodium glutamate (MSG) and 2-phenoxyethanol are used as stabilizers in a few vaccines to help the vaccine remain unchanged when the vaccine is exposed to heat, light, acidity, or humidity.
* Thimerosal is a mercury-containing preservative that is added to vials of vaccine that contain more than one dose to prevent contamination and growth of potentially harmful bacteria.
[edit] Role of preservatives
Many vaccines need preservatives to prevent serious adverse effects such as Staphylococcus infection that, in one 1928 incident, killed 12 of 21 children inoculated with a diphtheria vaccine that lacked a preservative.[34] Several preservatives are available, including thiomersal, phenoxyethanol, and formaldehyde. Thiomersal is more effective against bacteria, has better shelf life, and improves vaccine stability, potency, and safety, but in the U.S., the European Union, and a few other affluent countries, it is no longer used as a preservative in childhood vaccines, as a precautionary measure due to its mercury content.[35] Although controversial claims have been made that thiomersal contributes to autism, no convincing scientific evidence supports these claims.[36]
