One of the main points that needs saying is epidemics can be faked by the likes of the CDC.

This allows ongoing massive sales in perpetuity for drugs such as in HIV or Hepatitis C, or vaccines such as hepatitis B vaccine. Conditions such as immunodeficiency or hepatitis have many causes and it is possible to scaremonger people into believing a viral epidemic has occurred.

Electron micrographs can also be faked with added contents to show whatever size or shape particle they want. Never trust a CDC released image of a virus.

Also serology tests can be scammed eg viral load in HIV (a non specific PCR test that gets suppressed by the anti-retroviral drugs supposed to treat HIV virus). Virology has been subject to much fraud since the supposed discovery of the tobacco mosaic virus...