COVID-19

==== Virus proteins ====
[[File:Fpubh-08-00383-g004.jpg|thumb|The association between SARS-CoV-2 and the [[Renin–angiotensin system|Renin-Angiotensin-Aldosterone System]] (RAAS)]]

Multiple viral and host factors affect the pathogenesis of the virus. The S-protein, otherwise known as the spike protein, is the viral component that attaches to the host receptor via the [[Angiotensin-converting enzyme 2|ACE2]] receptors. It includes two subunits: S1 and S2. S1 determines the virus-host range and cellular tropism via the receptor-binding domain. S2 mediates the membrane fusion of the virus to its potential cell host via the H1 and HR2, which are [[heptad repeat]] regions. Studies have shown that S1 domain induced [[IgG]] and [[IgA]] antibody levels at a much higher capacity. It is the focus spike proteins expression that are involved in many effective COVID‑19 vaccines.<ref name="pmid33340022">{{#invoke:cite journal || vauthors = Dai L, Gao GF | title = Viral targets for vaccines against COVID-19 | journal = Nature Reviews. Immunology | volume = 21 | issue = 2 | pages = 73–82 | date = February 2021 | pmid = 33340022 | pmc = 7747004 | doi = 10.1038/s41577-020-00480-0 |issn=1474-1733 }}</ref>

The M protein is the viral protein responsible for the transmembrane transport of nutrients. It is the cause of the bud release and the formation of the viral envelope.<ref name="Boopathi-2020">{{#invoke:cite journal || vauthors = Boopathi S, Poma AB, Kolandaivel P | title = Novel 2019 coronavirus structure, mechanism of action, antiviral drug promises and rule out against its treatment | journal = Journal of Biomolecular Structure & Dynamics | pages = 3409–3418 | date = April 2020 | volume = 39 | issue = 9 | pmid = 32306836 | pmc = 7196923 | doi = 10.1080/07391102.2020.1758788 }}</ref> The N and E protein are accessory proteins that interfere with the host's immune response.<ref name="Boopathi-2020" />