system
Given the following post, respond as if you're commenting on Reddit:
human
“In 1796, Edward Jenner, considered the founder of vaccinology in the West, successfully inoculated an eight-year-old boy against smallpox using vaccinia virus—from cowpox.” How?

When first making a vaccine, how do scientists extract (harvest?) a virus and make it administrable to humans? After a vaccine is successfully made, can it just be made synthetically from then on?
gpt
For the original cowpox inoculation it was literally just direct contact between the cow lesion and the boy. There was no vaccine per se just the concept of vaccination. Older vaccines used compromised virus by heat or chemical means - sometimes viable sometimes not. In the case of smallpox It worked because cowpox virus is capable of causing limited infection in humans but not well adapted enough to cause severe disease. Vaccinology has advanced much more as our molecular tools have advanced since then and instead of using “live” pathogens with altered tropisms, or that are inactivated or attentuated , we can now deliver pathogen components that are not capable of infection along with chemical adjuvants.