When we pay a visit to hospital, the sight of an NHS uniform normally brings with it a sense of professionalism, trust and public confidence.

Most of us view a smartly-dressed doctor or nurse in their official attire as a reassuring presence on a ward and a calming influence during times of distress.

But the same cannot be said when we bump into the same member of staff in their scrubs at a supermarket or picking up their children from school.

Whether rightly or wrongly, these workers have sometimes faced criticism for wearing their uniforms in public and blamed for contributing to the spread of nasty bugs.

Commenting on a WalesOnline story on a norovirus outbreak at the University Hospital of Wales in Cardiff earlier this month, Adele Bradford said: "I always wondered why on earth it's okay to walk around Tesco with it on then go to work. Surely it makes sense to dress when you arrive at work."

Similarly, Linzee Gittoes said: "I have been shopping and I have seen auxiliary nurses and cleaners in their work clothes, so they have been on wards and then are doing their shopping in contaminated clothes."

And Marie Jones Kerr added: "Uniforms [should be] kept in the hospital. We see nursing staff on buses etc. wearing their uniform. Anything could be picked up."

In response to these claims, we decided to take a closer look at the current guidelines on NHS uniform, where and when they are allowed to be worn and how prone they are to spreading germs.

What is the general guidance on wearing NHS uniform in work?

The Royal College of Nursing (RCN) has produced extensive guidance on uniforms and work wear for nurses.

Its report states that there are seven key principles when it comes to uniform in the workplace. It should:

There are also a number of legal requirements relating to keeping staff safe in work and ensuring that they are given suitable attire to prevent them, and others, from harm.

The NHS faces a number of pressures in the coming months

What harm can NHS uniforms cause?

Studies have shown that uniforms may become contaminated by potentially disease-causing bacteria, including Staphylococcus aureus, Clostridium difficile and glycopeptide resistant enterococci (GRE).

Although it has been suggested that uniforms act as a "reservoir" for transmission of infection in hospitals, no evidence has ever been published to back this up.

RCN guidance states "maximum contamination" occurs in areas of greatest hand contact such as pockets, cuffs and apron areas. This can, as a consequence, potentially cause the re-contamination of washed hands.

However, it is estimated that a third of the organisms present originated from the person's skin rather than the uniform itself.

What are NHS staff allow to wear on duty?

According to the Welsh Government's All Wales NHS Dress Code, NHS staff should "present a professional image in the workplace".

It also has some very specific requirements about what should, and more importantly should not, be worn on duty.

This includes:

Should NHS staff be wearing their uniforms in public?

The RCN and Welsh Government are pretty clear on this.

They state that NHS staff are not permitted to display their uniforms in any public areas.

However, they are allowed to travel back and forth to work, including on public transport, wearing their uniforms as long as they are hidden with a coat over the top.

The Welsh Government All Wales NHS Dress Code report states: "Where changing facilities are available, staff must change out of their uniform at the end of a shift before leaving their place of work.

"Where changing facilities are not available staff should ensure their uniform is covered up before leaving their place of work.

"Staff must not wear their uniforms in public places, for example, shops. If staff need to enter public places in the course of their duties they must make every effort to cover their uniforms.

"Staff who are permitted to wear a uniform to and from work, or work in the community setting, must cover their uniform when travelling."

Can NHS staff wash their uniforms in work?

The RCN report states that all acute healthcare organisations should provide laundering facilities for staff uniforms, so staff are able to change out of uniforms after work and have clean uniforms available for each shift.

Hold on a minute...shouldn't the public take the blame for the spread of bugs too?

Absolutely. It is thought that members of the public, including visitors to hospitals, are the main cause of the spread of harmful bacteria.

Health boards across Wales, particularly in winter, often have to control the spread of viruses by temporarily shutting wards to visitors and new patients.

How to protect yourself from common bugs:

You can stop the spread of bugs by: