So if you are not Patrick, you are aware of COVID-19. You will also be aware that if you ask all 7.8 (- 11300) billion people on this planet whether wearing a face mask will help reduce the spread of the virus, you will get exactly 50% responses saying yes, it will help, and 50% of the responses will claim that it does not help.
... if you do not have these [COVID-19] symptoms, you do not have to wear masks because there is no evidence that they protect people who are not sick.
followed by this highly contradictory statement:
However, if you are healthy, but you are taking care of a person who may be infected with the new Coronavirus, then you should wear a mask.
Logically speaking, seeing that the second statement states you are not sick, and considering a mask can protect both you from breathing in a sick person's cough droplets and also someone else from getting infected by your cough droplets, the use of a mask in this case is not to protect the sick person from yourself, but to protect you from the sick person.
So she just stated that a mask does not protect healthy people but that it does protect healthy people.
I later found this article going into more depth into this nonsense. No wonder people are confused.
The answer is actually not that hard to figure out for yourself. If you wear a mask, the first issue to address is the size of the virus and the mask density. The virus is approximately 125nm in size, much smaller than even an N95 mask's pores. However, the virus is highly unlikely to travel in isolation. It usually travels in tiny droplets being coughed up by someone infected. These droplets are much larger and will get caught in the mask. If the mask is worn properly, and replaced frequently, and other protocols followed (not touching the mask, etc) then it will reduce the amount of droplets you can expel as well as breath in.
However, the virus can also enter your eyes. Since the mask does not cover your eyes it cannot be perfectly effective. It only reduces risk, probably much more so if you are sick than if you are healthy, but since it reduces the amount of droplets you will breathe in, it has to improve your chances. How much is hard to say - it depends on how easy droplets getting in to your eyes can infect you.
So my conclusion is - yes it helps whether you are ill or not. It helps much more if you are ill to reduce the chances of your cough droplets infecting someone else, though your hands touching things will render this moot. Just strange that the WHO cannot give a clear answer on a subject that clearly has an answer of: It depends.