Researchers assessed the protective ability of a chimpanzee adenovirus (simian Ad-36)-based SARS-CoV-2 vaccine (ChAd-SARS-CoV-2-S) that encodes a pre-fusion stabilized spike protein (S) in mice.  Upon administering the vaccine intramuscularly, the mice exhibited protection against lung inflammation, pathology, and infection.  The mice also exhibited cell-mediated and humoral immune responses upon intramuscular administration of the vaccine.  However, high amounts of viral RNA of SARS-CoV-2 was still detected in the lungs of the mice after intramuscular vaccine administration.  Contrastingly, upon intranasal administration of the vaccine in a single dose, significantly high amounts of neutralizing antibodies, anti-SARS-CoV-2 IgA, and T cell responses were induced, offering complete protection against SARS-CoV-2 infection in the lower and upper respiratory tracts.  Thus, ChAd-SARS-CoV-2-S has a strong potential for preventing against and protecting from SARS-CoV-2 infection.


Single-Dose Intranasal ChAd-SARS-CoV-2-S Vaccine 

- A single-dose intranasal ChAd vaccine protects upper and lower respiratory tracts against SARS-CoV-2

Johns Hopkins University

Viral-Vector vaccines genetically engineer another virus, referred to as vectors, to carry genetic materials from the coronavirus and produce coronavirus proteins in the human body. These vectors are weakened and does not cause disease. Two main types are (shown in image):

Viral-Vector Vaccines for COVID-19

Hassan, A. O., Kafai, N. M., Dmitriev, I. P., Fox, J. M., Smith, B. K., Harvey, I. B., . . . Diamond, M. S. (2020). A single-dose intranasal ChAd vaccine protects upper and lower respiratory tracts against SARS-CoV-2. Cell. doi:10.1016/j.cell.2020.08.026

A single-dose intranasal ChAd vaccine protects upper and lower respiratory tracts against SARS-CoV-2

- Using Ad5 by CanSino Biologics
- Using Chimpanzee adenovirus  (ChAdOx1 nCoV-19) by The University of Oxford
- Using Ad26 by Johnson & Johnson
- Using NCT04276896/NCT04299724 by Shenzhen Geno-Immune Medical Institute

Viral-Vector Vaccines in Clinical Trial for COVID-19

Information gained from studies done on both the immune response and vaccine development to related betacoronaviruses can help us gain insight on the immunopathology of SARS-CoV-2 and guide the devlopment of a vaccine. 

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