Advances of human oral viral vaccine development / 生物工程学报

Development of a vaccine that can simultaneously induce effective mucosal immunity and systemic immunity is an ideal goal to prevent mucosal pathogenic infections. The digestive tract has many sites for inducing mucosal immunity, including the mouth, stomach and small intestine. An ideal oral viral vaccine can not only induce better local and distal mucosal immunity, but also produce better systemic immunity. The oral viral vaccine has also attracted much attention because of its painless vaccination, self-administration and other advantages. Due to the complexity of human digestive tract environment and mucosal immunity, only three oral attenuated live vaccines have been successfully marketed for human use. This review summarizes the characteristics of gastrointestinal mucosal immunity, the current types and research status of oral viral vaccines, and the challenges faced by oral viral vaccines, with the hope to facilitate the research and development of oral viral vaccines for human use in China.

Effectiveness of inactivated hantavirus vaccine on the disease severity of hemorrhagic fever with renal syndrome

BACKGROUND: An inactivated Hantaan virus vaccine (iHV) has been broadly used as a preventive strategy for hemorrhagic fever with renal syndrome (HFRS) by the South Korean Army. After the vaccination program was initiated, the overall incidence of HFRS cases was reduced in the military population. While there are about 400 HFRS cases annually, few studies have demonstrated the efficacy of the iHV in field settings. Therefore, this study aimed to evaluate the iHV efficacy on HFRS severity. METHODS: From 2009 to 2017, HFRS cases were collected in South Korean Army hospitals along with patients’ vaccination history. HFRS patients were classified retrospectively into two groups according to vaccination records: no history of iHV vaccination and valid vaccination. Vaccine efficacy on the severity of acute kidney injury (AKI) stage and dialysis events were investigated. RESULTS: The effects of the iHV on renal injury severity in between 18 valid vaccinated and 110 non-vaccinated patients were respectively evaluated. In the valid vaccination group, six of the 18 HFRS patients (33.3%) had stage 3 AKI, compared to 60 of the 110 (54.5%) patients in the non-vaccination group. The iHV efficacy against disease progression (VEp) was 58.1% (95% confidence interval, 31.3% to 88.0%). CONCLUSION: The iHV efficacy against the progression of HFRS failed to demonstrate statistically significant protection. However, different severity profiles were observed between the iHV and non-vaccination groups. Additional studies with larger populations are needed to demonstrate the effectiveness of the iHV in patients with HFRS.

Strategies for producing high-yield viral vaccine antigens / 生物工程学报

Vaccination is an important strategy to prevent infectious diseases. However, low antigen yield of vaccine producing strains may lead to high cost of vaccines, low antigen production and vaccine failure. In recent years, many efforts have been made to improve the antigen yield of many vaccines. This mini-review summarizes various methods for increasing the antigen yield for vaccine production, including genetic modification of viruses, improvement of the adaptation of viruses to cells, and optimization of antigen expression systems and manufacturing procedures. Furthermore, we discuss the advantages and the problems of current strategies, as well as indicate the perspectives.

Optimization of a freeze-drying cycle of a viral vaccine based on changes in temperature, time and geometry of the vials.

The freeze-drying process is used in pharmaceutical industry, however in terms of process management, the process must be avoided at all cost because it has several disadvantages such as high equipment investment, high energy demand, a process that requires long times and products easily to moisturize and fragile and needs to be carefully packed and stored. This work aims at reducing the freeze-drying cycle time of a viral product and consider loading this product at subzero temperatures to increase productivity of this product. Experiments were carried out with freeze-drying cycles with less 15 and 20h in comparison to the original cycle. The experiments were performed with the same formulation of the commercial batch and using a pilot freeze dryer. Modifications were made in the physical properties of the current freeze-drying cycle (temperature, pressure and time) and the loading temperature of the product, without changing the formulation of the vaccine or primary loading. Samples of the lyophilized product trial were analyzed for their appearance, performance, residual moisture, strength and accelerated thermostability in the amount currently used by the company quality control. All the results were within the specifications of the company were close to or better when compared to commercial batches.