Vaccination is the most cost-effective strategy to prevent and control SARS-CoV-2 infection, which plays an importantrole in maintaining global public health and ensuring human health. Adjuvants, as crucial components in vaccine development,can make up for the potential antigen immunogenicity deficiencies by enhancing the speed, intensity and persistence ofimmune response, and significantly improve the efficacy of vaccines, being a pivotal role in improving the immune effect ofSARS-CoV-2 vaccines. There are many types of adjuvants, which are suitable for different types of vaccines. For example,the inactivated SARS-CoV-2 vaccine mostly uses aluminum adjuvant, the recombinant protein vaccines adapt to compositeadjuvants, and the mRNA vaccines rely on lipid nanoparticle(LNP) delivery platform. In this paper, the classification andmechanism of adjuvants, their application in vaccines and new ideas for development of broad-spectrum SARS-CoV-2 vaccineadjuvants were reviewed, providing references for preparing innovative adjuvants with good safety and effectiveness, so as tocontinuously improve the immune efficacy of SARS-CoV-2 vaccines and cope with the continuous variation of SARS-CoV-2.

Objective To explore the effects of different weeks of high intensity interval training (HIIT) and moderate intensity aerobic exercise on maximal oxygen uptake (VO2max) and the expression of the skeletal muscle oxidative capacity related factor AMP-activated protein kinase (AMPK) and peroxisome proliferators γactivated receptor coativator-1-α (PGC-1α),so as to provide the basis for the choice of effective load intensity.Methods One hundred and twenty 6-week-old SPF male Wistar rats were equally randomized into 3 groups according to their body weight:a sedentary control group (not receiving any exercise),a moderate-intensity exercise group (undergoing 50-min continuous running at an intensity of 60％-70％ VO2max) and a HIIT group (conducting 3-min running at 90％ VO2max interspersed with 3-min recovery periods at 50％ VO2max and repeating that process 6 times,with a 7-min warm-up and cool-down period at 70％ VO2max).All rats except those in the control group exercised five days a week and 50min per day.All rats were measured their weight at 8:00-9:00am every Sunday.Soleus was taken from ten randomly chosen rats of each group at 2nd,4th,6th and 10th week after the onset of the intervention.The VO2max test was done before taking muscles.Western blotting was used to detect the protein expression of AMPK and PGC-1α.Results (1) Both the exercise duration and mode had a significant impact on rats' body weight,and they had interaction with each other (P＜0.01).(2) The average PGC-1α expression in the skeletal muscle of 10-week HIIT group were significantly higher than those in the control group (P＜0.05),and the average VO2max at the same time was also significantly higher than the other two groups.(3) In the HIIT group,the average VO2max at the 10th week was significantly higher than that at the 2nd,4th and 6th week (P＜ 0.05).The average protein expression of AMPK in the skeletal muscle at the 4th week in the moderate-intensity exercise group was significantly higher than that at the 2nd and 6th week of the same group,and that at the 2nd week of the control group (P＜0.05).The average protein expression of PGC-1α in the HIIT group from the 2nd to the 10th week was significantly higher than the control group at the 2nd week (P＜0.05).(4)The protein expression of PGC-1α was significantly correlated with temporal variation of VO2max in the HIIT group (P＜0.05).Conclusion Ten-week HIIT can effectively promote the expression of AMPK and PGC-1α in skeletal muscles and the maximal oxygen uptake.It plays a more quick and effective role in improving oxidant capacity and cardiorespiratory endurance of skeletal muscles than traditional moderate-intensity exercises.