Facemasks, gloves and other protective gear can help stop the spread of coronavirus, in the right circumstances.
Some people are also making homemade masks - and Americans are now being advised to use them in public - but are they safe?
Why doesn't everyone wear a mask?
The World Health Organization (WHO) currently says only two groups of people should wear protective masks, those who are:
- sick and showing symptoms
- caring for people suspected to have the coronavirus
Masks are not recommended for the general public because:
- they can be contaminated by other people's coughs and sneezes or when putting them on or removing them
- frequent hand-washing and social distancing are more effective
- they might offer a false sense of security
Coronavirus is spread by droplets that can spray into the air when those infected talk, cough and sneeze. These can enter the body through the eyes, nose and mouth, either directly or after touching a contaminated object.
However, experts at the WHO are now exploring whether the general public might benefit from wearing masks. The group will examine research on whether the virus can be projected further than previously thought.
Do homemade face masks work?
Americans are now advised to use clean cloth or fabric to cover their faces whilst in public. Officials say medical masks are in short supply and should be left for healthcare workers.
Only the sick, or those caring for patients of coronavirus, had previously been told to wear masks. But US officials hope the new rules could stop people without symptoms unknowingly spreading coronavirus.
However, reusable cloth masks are also not recommended and may even increase the chance of infection, say European advisers.
They say there is a high chance virus particles could go through cloth. Problems with moisture could also mean the cloth retains the virus, they warn.
The UK is not advising most people to wear either medical or homemade masks. Health Secretary Matt Hancock says the government is following medical and scientific advice on their use.
England's deputy chief medical officer Prof Jonathan Van Tam says he does not believe that healthy people wearing them in the UK would reduce the spread of the disease. "What matters now is social distancing," he says.
Despite this, there is lots of advice on how to make face masks online, with some sites suggesting the best options.
However, homemade masks are not regulated whereas officially-made ones have to meet safety requirements.
What do I need to know about the coronavirus?
What is the best type of mask?
In hospitals, different types of mask offer different grades of protection.
The most protective is an FFP3 or, alternatively, an N95 or an FFP2.
Experts do not recommend the public use these masks. They are for healthcare workers in close contact with coronavirus patients and at highest risk of encountering infected airborne droplets.
Other NHS staff in lower-risk situations can wear a surgical mask, latest guidelines say. That means healthcare workers within one metre of a patient with possible or confirmed Covid-19, and it includes staff working in hospitals, primary care, ambulance trusts, community care settings and care homes.
What else can protect against coronavirus?
Gloves and other protective wear are recommended for NHS staff working in places where they could encounter coronavirus.
Again, staff in the highest-risk scenarios are advised to wear fuller protection, rather than a simple apron, gloves, mask and goggles.
The general public are not advised to wear gloves or any other protective gear.
To protect yourself from coronavirus, the NHS recommends:
- Wash hands with soap and water often, for at least 20 seconds and immediately on returning home
- Use hand sanitiser gel if soap and water are not available
- Cover your mouth and nose with a tissue or your sleeve - not your hands - when you cough or sneeze
- Put used tissues in the bin immediately and wash your hands afterwards
- Do not touch your eyes, nose or mouth if your hands are not clean