First norovirus symptoms - hour-by-hour guide to vomiting bug sweeping the UK

Also known as the winter vomiting bug, norovirus is a contagious illness that spreads quickly as the virus can live on infected surfaces for days. But what are the initial norovirus symptoms, and how do you know if you've been exposed?

Along with Halloween, Bonfire Night and the clocks going back, norovirus is one of those seasonal delights that rears its head every autumn.

It feels like most of us are sick right now, with a nasty bug sweeping the UK and making people feel awful. NHS figures show infections were up 29 per cent between September 23 and October 6 - double the usual outbreak level for that time of year.

And experts are warning it's only going to get worse, with the threat of a 'quadrupledemic' looming this winter. The relatively new Covid variant XEC continues to spread across the UK, while seasonal rates of flu and respiratory syncytial virus (RSV) are also expected to rise as the mercury plummets. On top of that, the norovirus superbug is expected to unleash havoc on the population, which could have a devastating impact on NHS bed space this winter.

GP Dr Roger Henderson previously told the Mirror : "When these infections overlap, they pose a heightened risk, especially for the elderly, young children, and people with existing health issues."

So how do you know when you have norovirus, also known as the winter vomiting bug? Unfortunately, it's not a subtle illness: nausea, vomiting and diarrhoea are the three main norovirus symptoms, but there are lots of other ways this tiny virus can make you feel utterly grim.

First norovirus symptoms

Exposure to the norovirus can happen at any time. The virus is present in vomit and stool, so if an infected person touches food, drink or surfaces that are then consumed or touched by someone else, they can pass on the bug without realising. Touching infected surfaces, like door knobs, bannisters or handles on public transport, then touching your mouth before you wash your hands is a sure-fire way to pick up the virus.

Symptoms can start as quickly as 10 hours after exposure, although in most cases illness starts 24 to 48 hours after you've been exposed. The first norovirus symptoms can be mistaken for other things: some people complain of a general sense of tiredness, headache, muscle aches and chills.

Some will have a low-grade fever as the virus gets to work inside their body. The next symptoms are nausea, which can last for hours, and stomach cramping. Finally, vomiting and diarrhoea begin, and generally don't stop until there's nothing left inside your body to expel.

The good news is norovirus is often short-lived, with most people experiencing symptoms for one or two days maximum. The danger comes from dehydration, which can come on quickly if you're unable to keep down any liquids. If your urine is dark coloured or smells strongly, your eyes appear sunken, you're feeling dizzy or lightheaded, you're peeing less often than usual, and you feel thirsty with dry mouth and lips, you are most likely dehydrated. Try to keep your fluid intake up with small sips of water or juice, and if you're worried about yourself or a family member - especially babies, children and elderly people - contact the NHS 111 helpline for advice.

How can I avoid getting norovirus?

Unfortunately there is no way to avoid exposure if you live, travel and work with other people. But you can decrease the risk by scrupulous hand hygiene: wash your hands with warm water and soap frequently, and always before eating. If someone in your household comes down with norovirus, disinfect contaminated surfaces they touch with household bleach-based cleaners, and wash soiled clothing and bedding as soon as possible.

Don't let an infected person handle food or water that you or anyone else is going to consume, and avoid eating or drinking from sources that could be contaminated. Alcohol-based hand sanitisers unfortunately don't kill the norovirus, so always opt for warm water and soap to wash your hands when you can.

An infected person will be contagious from as soon as they start feeling unwell until three days after the symptoms end, so you should avoid going to work or mixing with other people for at least 48 hours after your last bout of vomiting or diarrhoea.