That part is well-covered when you google “what happens when you sneeze in space”. What I couldn’t find was what happened to the person who sneezed.
Snot will go 3-6 feet. HEPA filters are too energy-expensive. But here’s the interesting bit:
For reasons scientists have not quite figured out, the immune system can go on the fritz in space: wounds heal more slowly; infection-fighting T-cells send signals less efficiently; bone marrow replenishes itself less effectively; killer cells — another key immune system player — fight less energetically. At the same time, the pathogens grow stronger, developing thicker cell walls, greater resistance to antimicrobial agents and a greater ability to form so-called biofilms that cling to surfaces. Dormant herpesvirus infections are known to become more active in space, and swabs of astronauts taken when they return to Earth show higher populations of staph on the skin, in the upper airway and in the colon. All of that means a single spark of a disease could burn out of control fast.
They don’t mention wounds draining because I assume NASA isn’t expecting little green men to use bullets.