Coronavirus disease 2019 vaccines: landscape of global studies and potential risks.

ABSTRACT: With the outbreak of the coronavirus disease 2019 (COVID-19) pandemic, the importance of vaccines in epidemic prevention and public health has become even more obvious than ever. However, the emergence of multiple severe acute respiratory syndrome coronavirus 2 variants worldwide has raised concerns about the effectiveness of current COVID-19 vaccines. Here, we review the characteristics of COVID-19 vaccine candidates in five platforms and the latest clinical trial results of them. In addition, we further discuss future directions for the research and development of the next generation of COVID-19 vaccines. We also summarize the serious adverse events reported recently after the large-scale vaccination with the current COVID-19 vaccines, including the thromboembolism caused by the AstraZeneca and Johnson & Johnson vaccines.

Quadrivalent influenza vaccine (Sinovac Biotech) for seasonal influenza prophylaxis.

INTRODUCTION: Quadrivalent Influenza Vaccine (Sinovac Biotech) is a quadrivalent split-virion-inactivated influenza vaccine approved in China in June 2020 for individuals ≥3 years of age. It contains 15 µg hemagglutinin per strain including A/H1N1, A/H3N2, B/Victoria, and B/Yamagata, which could potentially improve protection against influenza B viruses. AREAS COVERED: In this review, we summarize the development of quadrivalent influenza vaccines in China and foreign countries, and assess the immunogenicity and safety from the phase I and III clinical trials of Quadrivalent Influenza Vaccine in individuals ≥3 years of age. We also discuss the potential application of Quadrivalent Influenza Vaccine in young children 6-35 months of age according to the results of the phase III trial. EXPERT COMMENTARY: The immunogenicity and safety profiles of Quadrivalent Influenza Vaccine containing two A and two B strains were comparable to the trivalent vaccines for the shared strains. The addition of a second B strain to the trivalent vaccine could induce superior immune responses for the alternate B strain. Since the two B strains co-circulated worldwide, the introduction of quadrivalent influenza vaccines has been expected to be a cost-effective strategy.

Fresh amniotic membraneversus acellular amniotic membrane for repair of the tendon sheath and prevention of tendon adhesion / 中国组织工程研究

BACKGROUND: Amniotic membrane has a unique structure that can block the penetration of certain substances, to ensure normal nutrition supply for the surrounded tissues, and is also characterized by anti-adhesion, good tissue compatibility, mild inflammatory reaction, few fibers and biodegradability. OBJECTIVE: To compare the effects of fresh amniotic membrane and acellular amniotic membrane to prevent adhesion and promote tendon healing during the repair of tendon sheath defects. METHODS: Sixty healthy male leghorn chickens were selected, and the model of tendon injury and tendon sheath defects was established at the third toes. The animal models were then randomly divided into three groups and underwent repair with fresh amniotic membrane (group A), acellular amniotic membrane (group B), and no treatment in control group (group C), respectively. Histological observation and biomechanical analysis of the third toes were performed after repair. RESULTS AND CONCLUSION: (1) Histological observation. Congestive edema and inflammatory response were found in all animals at 2 weeks after repair, but mildest in the group A and severest in the group C. These inflammatory responses gradually alleviated over time in the three groups. At 12 weeks after repair, the new tendon sheath formed in all the animals, which was more mature than that at 4 weeks after repair. The synovial cells on the surface of the tendon sheath were arrayed tidily with dense structure in the groups A and B, but in the group C, the synovial cells were distributed disorderly with loose structure and prominent fibrous tissues. (2) Biomechanical analysis. Tendon sliding distance in the groups A and B was significantly larger than that in the group C at 4, 8, 12 weeks after repair (P < 0.05), but there were no significant difference in the distance between the groups A and B (P > 0.05). At 4 and 8 weeks after repair, the maximum tensile strength was largest in the group A, sequentially followed by group B and group C (P < 0.05), but there were no significant difference among the three groups at 12 weeks after repair (P > 0.05). To conclude, both fresh amniotic membrane and acellular amniotic membrane can promote tendon healing and prevent the adhesion of tendon through tendon sheath reconstruction, but the fresh amniotic membrane is preferred to promote early tendon healing compared with acellular amniotic membrane.

Fresh amniotic membraneversus acellular amniotic membrane for repair of the tendon sheath and prevention of tendon adhesion / 中国组织工程研究

BACKGROUND: Amniotic membrane has a unique structure that can block the penetration of certain substances, to ensure normal nutrition supply for the surrounded tissues, and is also characterized by anti-adhesion, good tissue compatibility, mild inflammatory reaction, few fibers and biodegradability. OBJECTIVE: To compare the effects of fresh amniotic membrane and acellular amniotic membrane to prevent adhesion and promote tendon healing during the repair of tendon sheath defects. METHODS: Sixty healthy male leghorn chickens were selected, and the model of tendon injury and tendon sheath defects was established at the third toes. The animal models were then randomly divided into three groups and underwent repair with fresh amniotic membrane (group A), acellular amniotic membrane (group B), and no treatment in control group (group C), respectively. Histological observation and biomechanical analysis of the third toes were performed after repair. RESULTS AND CONCLUSION: (1) Histological observation. Congestive edema and inflammatory response were found in all animals at 2 weeks after repair, but mildest in the group A and severest in the group C. These inflammatory responses gradually alleviated over time in the three groups. At 12 weeks after repair, the new tendon sheath formed in all the animals, which was more mature than that at 4 weeks after repair. The synovial cells on the surface of the tendon sheath were arrayed tidily with dense structure in the groups A and B, but in the group C, the synovial cells were distributed disorderly with loose structure and prominent fibrous tissues. (2) Biomechanical analysis. Tendon sliding distance in the groups A and B was significantly larger than that in the group C at 4, 8, 12 weeks after repair (P < 0.05), but there were no significant difference in the distance between the groups A and B (P > 0.05). At 4 and 8 weeks after repair, the maximum tensile strength was largest in the group A, sequentially followed by group B and group C (P < 0.05), but there were no significant difference among the three groups at 12 weeks after repair (P > 0.05). To conclude, both fresh amniotic membrane and acellular amniotic membrane can promote tendon healing and prevent the adhesion of tendon through tendon sheath reconstruction, but the fresh amniotic membrane is preferred to promote early tendon healing compared with acellular amniotic membrane.