ABSTRACT
SARS-CoV-2 continues to accumulate mutations to evade immunity, leading to breakthrough infections after vaccination. How researchers can anticipate the evolutionary trajectory of the virus in advance in the design of next-generation vaccines requires investigation. Here, we performed a comprehensive study of 11,650,487 SARS-CoV-2 sequences, which revealed that the SARS-CoV-2 spike (S) protein evolved not randomly but into directional paths of either high infectivity plus low immune resistance or low infectivity plus high immune resistance. The viral infectivity and immune resistance of variants are generally incompatible, except for limited variants such as Beta and Kappa. The Omicron variant has the highest immune resistance but showed high infectivity in only one of the tested cell lines. To provide cross-clade immunity against variants that undergo diverse evolutionary pathways, we designed a new pan-vaccine antigen (Span). Span was designed by analyzing the homology of 2675 SARS-CoV-2 S protein sequences from the NCBI database before the Delta variant emerged. The refined Span protein harbors high-frequency residues at given positions that reflect cross-clade generality in sequence evolution. Compared with a prototype wild-type (Swt) vaccine, which, when administered to mice, induced serum with decreased neutralization activity against emerging variants, Span vaccination of mice elicited broad immunity to a wide range of variants, including those that emerged after our design. Moreover, vaccinating mice with a heterologous Span booster conferred complete protection against lethal infection with the Omicron variant. Our results highlight the importance and feasibility of a universal vaccine to fight against SARS-CoV-2 antigenic drift.
ABSTRACT
COVID-19, as a rampant health crisis, lies at the basis of fluctuating perceptions affecting decreased demand among travelers. Recent studies have witnessed a growth of interest in the interactions between tourists' behaviors and other factors with the potential to moderate such behavior during travel. However, it remains to be discussed whether the influence of demographic aspects, especially cultural and gender differences, on tourism behaviors will be more prominent during COVID-19. The current empirical research aims to integrate demographic variables, including gender and culture, with tourists' behavior in terms of their choice of companions, travel destinations, and mode of transportation. According to the research findings, people in other countries have greater desire to travel than Chinese tourists who, in any case, prefer to travel with friends. Tourists from other countries are more willing to travel by plane and by car. Males show a more positive attitude than females to these means of transportation. Moreover, the interactive effect of gender and nationality reveals that female travelers from mainland China put the train or bus top on their agenda. These theoretical findings have the potential to provide actionable insights into how policymakers and service providers can make adjustments to bring back tourism stifled by COVID-19.
ABSTRACT
As the vaccine was successfully developed, the spread of the epidemic (COVID-19) was effectively controlled. But there are still thousands of people affected COVID-19 after being vaccinated. Neutralizing activity has become a critical method for quantifying neutralizing antibody against SARS-CoV-2. However, limited to the strict conditions of cold chain transportation, the neutralizing activity test has not been widely promoted. In this study, a room-temperature-storable chemiluminescence freeze-drying mixes for SARS-CoV-2 neutralizing antibody detection was developed to decrease the cost of lyophilization step for promoting its application in third world countries. Several freeze concentrated solutions were used to protect the antigen bioactivity. The mixes can be stored at room temperature over 12 months and still exhibited great accuracy and precision. Thus, the proposed room-temperature-storable chemiluminescence freeze-drying mixes offers a cheap and stable storage method for SARS-CoV-2 neutralizing antibody detection and shows a great potential for promoting the neutralizing activity test.