Originally Posted by Libertine

I'll take that to mean that no, you have no idea whatsoever of how it works.

So I'll go ahead and explain it.

When an infected person sneezes, coughs into his hand, wipes his nose, etc., he contaminates things for the period of time the virus can stay alive outside of the human body. Now, this can cause him to directly infect someone else, or - what you are focusing on - cause an indirect infection.

While indirect infections are indeed a risk, they're limited by the fact that outside of a living body, the virus won't stay alive for all that long. Moreover, because the virus does not have any cells to use to replicate itself, no new viral particles are being created.

So if someone infected with the flu goes all around a hospital, sneezing and coughing everyhwhere, if he fails to infect anyone it won't be long before the virus has died off again and everything is safe once more.

However, if he does infect some people, they will also start spreading the virus around.

And that's where vaccinations come in. By vaccinating health care workers, you greatly increase chances that the virus from one patient will die off before it gets the chance to infect someone else. And keep in mind that the flu virus, for example, only stays alive for a few minutes on human skin.

It's the same concept as herd immunity: the lower the chances of a person infecting someone else, the lower the chances of a full-blown outbreak. Because outbreaks depend on each case of infection causing one or more additional cases of infection before ending.

Now, if health care workers simply get vaccinated and follow proper protocol, chances of the infection being spread are quite small. Sure, a few infected patients might infect a few others, but there's a decent chance that there's enough distance in space and time between contact with infected individuals and susceptible individuals to prevent infections from spreading out.

On the other hand, without vaccinations, health care workers themselves can actually become sources of infection rather than just uninfected short-term carriers. You don't need to be an immunologist to see just how much more likely and how much faster that makes the spread of infections.