Masks do help with Covid19. Use them. It's the polite thing to do.

There's a lot of snootiness about masks and the Coronavirus: "Oh, there's no proof that they work".
This statement is not true. See the foot of this post.

Surgeons have been using masks since 1897 in order to stop droplets coming from their mouth during breathing, speaking and coughing from getting into the surgical wound in front of them.

Yes, there is no proof, no double blind crossover clinical trial of whether unmasked surgeons would have more post-operative infections than a masked surgeon.

The fact is that if we wear masks in this Covid outbreak, we will not spray people in front of us with droplets as we breathe, talk, sneeze or cough.

It is polite and considerate to wear masks, given that we may be shedding Coronavirus even while we feel perfectly well. 

So masks protect others and will help to reduce the rate at which the virus spreads.
Which is very important.

They also protect the wearer to some degree.

Masks stop us touching our nose and mouths with our potentially infected hands.

Masks also can stop droplets from someone else’s speech getting directly into our mouths.

Masks are useful, even though viruses can still get into our lungs through the gap between the mask and our noses. (Consider closing this gap with micropore tape).

The main problem with masks is that they make your glasses steam up (the tape may help this) and they tend to pull your hearing aids out, which can be a problem for older people, but then it is older people who are going to benefit from mask-wearing.

So, overall, masks do help. 

Use them.

It's the polite thing to do.

Some studies:

"adherence to mask use significantly reduced the risk for Influenza Like Illness-associated infection" Macintyre et al  <that is, it protected the wearer from acquiring their child's 'flu

"There is some evidence to support the wearing of masks or respirators during illness to protect others, and public health emphasis on mask wearing during illness may help to reduce influenza virus transmission". Cowling et al, (Review)


"Impregnation of copper oxide into respiratory protective face masks endows them with potent anti-influenza biocidal properties without altering their physical barrier properties". Borkow et al. 

"The use of protective masks has been shown to reduce the spread of respiratory viruses, especially when used by individuals in enclosed spaces or in close contact with a person with influenza-like symptoms" Jefferson et al 

[This post has been edited 12/4/2020 removing qualifier on double-blind trial]