Excipients used with other vaccine technologies
Excipients used in other types of vaccines (live weakened/attenuated virus, killed virus, viral vector, and protein-based) include preservatives such as thimerosal to prevent contamination; adjuvants, which most commonly are aluminum salts, to boost the immune response; and stabilizers including sugars and gelatin. Trace amounts of cell-culture materials, inactivating ingredients used to kill viruses or inactivate toxins, and antibiotics may also be present. A list of the substances in US-approved vaccines other than the active ingredients can be found on the Centers for Disease Control and Prevention website (1).
One of the biggest challenges for many vaccines, not just mRNA products, is their instability and the need for low-temperature storage. Researchers at the University of Texas at Austin have developed a potential solution—a thin film technology that can preserve live viruses, bacteria, antibodies, and enzymes without refrigeration for months to in some cases a
few years (2).
1. CDC, “Vaccine Excipient Summary,” February 2020.
2. I. Barjovicm, et. al., Science Advances, 6 (10) (March 4, 2020).