The AVT editor will talk about the application of liposomes in herpes zoster vaccines. Liposomes play an adjuvant role in herpes zoster vaccines. When it comes to adjuvants, the AS (adjuvant system) adjuvant system is a series of human vaccine adjuvants developed by GlaxoSmithKline (GSK), consisting of four types: AS01, AS02, AS03, and AS04. Among them, AS01 is a liposome adjuvant containing immunostimulant monophosphate lipid A (MPL) and soapberry saponin QS-21, and AS02 is a water in oil emulsifier of MPL and QS-21. The recombinant herpes zoster vaccine (CHO cells) approved for domestic market in May last year uses AS01B as an adjuvant for the prevention of herpes zoster in adults aged 50 and above.

　　

　　

　　Herpes zoster is a infectious diseases caused by varicella zoster virus. It usually appears as a rash on one side of the body accompanied with pain and itching, lasting for two to four weeks. It tends to occur in adults and the incidence rate increases significantly with age. Common complications include secondary Gan infection and postherpetic neuralgia, which can last for months to years and seriously affect patients' normal work and life. Research data shows that over 90% of adults are at risk of contracting shingles, and the risk of contracting shingles increases sharply among people over 50 years old. Nearly 3 million adults in China are affected by shingles every year, and there was a lack of effective prevention and treatment methods for the disease in the past, so there is an urgent need for relevant drugs in clinical practice.

　　

Vaccines containing AS01 adjuvant can generate strong and long-lasting immune responses, inducing rapid and short-term innate immune cell and molecular responses, reaching a peak on the first day after injection, gradually decreasing, and returning to pre injection levels on the seventh day. Its mechanism of action comes from two immunostimulants, MPL and QS-21: MPL activates the innate immune system through Toll like receptor 4 (TLR4), directly activating antigen-presenting cells expressing TLR4, stimulating cytokine secretion and co stimulatory molecule expression; QS-21 is a saponin that can promote antigen-specific antibody responses and activate cytotoxic CD8+T cells. However, QS-21 has hemolytic properties and needs to be used in combination with cholesterol and liposome forms to eliminate side effects. Therefore, the AS01B adjuvant system used in the herpes zoster vaccine also includes diacylphosphatidylcholine (DOPC) and cholesterol.

The recombinant herpes zoster vaccine approved this time is an imported product of SHINGRIX from the United States. SHINGRIX was approved by the FDA for marketing in October 2017 and competes with Merck's ZOSTAVAX in the market. The product is provided in two component packaging forms: a small bottle of freeze-dried varicella zoster virus glycoprotein E antigen powder and a small bottle of adjuvant suspension (without syringe or needle packaging). The two components are mixed before use, and the antigen is dissolved and administered intramuscularly. The specific prescription is as follows: