Figures & data
Figure 1. Development timeline of Ad5-nCov.
Figure 2. Adenovirus genome and vector structure. A) Adenovirus particlestructure comprises an icosahedral shape without an envelope, and iscomposed of hexon protein, penton proteins, and fibrin. B) Adenovirusgenome structure is around 36kb in total length, containing 4 earlygenes (E1~E4) and 5 late genes (L1~L5), with each end possessing aninverted terminal repeat (ITR). C) The first-generation adenovirusvector is roughly 35kb in length. The vector is replication-deficientas the E1 gene associated with adenovirus replication is deleted.Additionally, the E3 gene, which is unrelated to replication, is alsodeleted, thus allowing the vector to carry the exogenous target geneup to approximately 8kb.
Figure 3. Schematicsof aerosolized Ad5-nCoV inhalation. The recombinant adenovirustype-5 vectored COVID-19 vaccine (Ad5-nCoV) utilizes a non-pathogenicadenovirus vector to deliver the genetic material of the S protein,resulting in precise immune system activation without the risk ofinfection. Additionally, when administered via oral inhalation usinga nebulizer, the vaccine can be aerosolized into particles anddelivered to the lungs, leading to the stimulation of a triple immuneresponse involving humoral, cell, and mucosal immunity.
Table 1. Listing of studies addressing heterologous prime-boost techniques of COVID-19 vaccines based on different platforms.