Test overview
https://www.cdc.gov/flu/professionals/diagnosis/overview-testing-methods.htm
Prepublica
https://www.propublica.org/article/coronavirus-tests-are-being-fast-tracked-by-the-fda-but-its-unclear-how-accurate-they-are
Virus image
https://newatlas.com/science/new-detailed-images-novel-coronavirus-covid19-niaid/
Virus shields
https://www.kqed.org/science/3616/a-virus-shield-that-protects-us-from-our-own-bacteria
Role of virus
https://www.sciencedirect.com/science/article/abs/pii/S0022283614003301
What are viruses
https://www.livescience.com/53272-what-is-a-virus.html
Exosomes
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3873490/
...
https://www.youtube.com/watch?v=Wnq87OEg31A