No they don't as Terry has posted below and this is why (as i have said several times) the Government need to make the message on people wearing masks clearer.All masks will protect the user Chippy. Valved masks only protect the user, not those around them, so are useless for stopping spread of the virus if the individual is infected. Surgical masks will protect both the user and others around them.
Thanks Terry that saved me a lot of typing.Non medical masks offer very little protection for the user. Their main purpose, if worn, is to limit the spread of infection by an infected person, say in the pre-symptomatic period.
This is what the WHO have to say about medical masks, let alone something you knocked out on that ancient Singer sewing machine which has been in the loft, using a pair of old pants having looked at a Youtube video, and when worn has huge gaps round the side.
Wearing a medical mask is one of the prevention measures that can limit the spread of certain respiratory viral diseases, including COVID-19. However, the use of a mask alone is insufficient to provide an adequate level of protection, and other measures should also be adopted. Whether or not masks are used, maximum compliance with hand hygiene and other IPC measures is critical to prevent human-to-human transmission of COVID-19.