How to avoid catching the ‘two bucket’ virus that’s closing hospital wards – and causes diarrhoea AND vomiting

If you have yet to be hit by what’s been dubbed ‘the two-bucket virus’ – it causes both diarrhoea and vomiting – then count yourself lucky.

Cases of norovirus have been rocketing, just as cases of flu start to level off after what was the worst outbreak for a decade hit before Christmas.

While cases always rise in the winter (norovirus is also called the winter vomiting bug), health officials have been surprised that numbers are surging so much as spring approaches.

Latest figures from NHS England, published last week, showed how the average number of patients in ­hospital with norovirus each day in the previous week rose to more than 1,000 for the first time this winter (1,012) – an increase of just under 10 per cent on the previous week.

That is the second week in a row that figures have been rising.

‘Why this is happening now is not exactly clear,’ says Andrew Easton, a professor of virology at the University of Warwick.

‘As expected, respiratory viruses such as Covid-19, respiratory syncytial virus (RSV), flu and the common cold are dropping back from their peak and are in decline. But norovirus has gone in the opposite direction.’

Symptoms include nausea, vomiting and diarrhoea, as well as a high ­temperature, abdominal pain and aching limbs.

It can take 12 to 48 hours for symptoms to appear once you’re infected. So, because the virus has an incubation period of several days, people are often unaware that they are carrying it until after they have passed it on.

The virus is having such an impact that hospitals are already closing wards to try to contain outbreaks of the illness.

The problem with norovirus is that it is highly infectious. It only takes less than 100 particles to make you sick, and people shed billions in their stools and vomit.

And while cases of infections, such as flu and Covid are ­dropping, they are still higher than at other points in the year – meaning health services may be easily overwhelmed. One theory is that multiple mutations of the norovirus are in ­circulation, meaning that people are recovering from one variant only to fall ill again soon after with another form.

Over the past two years, there has been a surge in the number of infections caused by genotype GII.17, which is particularly good at mutating sufficiently quickly to be able to infect people multiple times, according to a study published recently in Nature Communications.

Meanwhile, strains of the GII.4 genotype, which caused 70 to 80 per cent of all the reported outbreaks between 2006 and 2016, are still circulating. This means that people who have already had norovirus this season may catch it again, as having one strain does not fully protect against the other.

‘Our immune system has a fantastic ability to identify a target, but that has a downside because if the target changes, your immunity may not be as strong against a new variant that appears,’ explains Professor Easton.

‘If you have multiple genotypes circulating simultaneously, you may be susceptible to be ­reinfected in the same season. That has been shown for RSV, as well as norovirus.’

Persistently wet weather throughout the UK has also helped to keep people indoors, making it easier for the virus to infect others, he explains.

Meanwhile, other infections are circulating, too – and in the early stages of recovery from a virus you may be more vulnerable to falling ill with another.

A study published in 2022 in The Lancet, involving nearly 7,000 hospital patients with Covid, found that 583 also had flu, RSV or adenoviruses (which typically cause colds and sore throats) – or a mixture of more than two.

‘When you develop one, it can reduce your immune defences to other illnesses,’ says Professor Peter Openshaw, a respiratory physician and mucosal immunologist at Imperial College London. ‘Developing more than one virus at the same time can lead to more severe outcomes.’

One of the best ways to protect yourself is to ensure your home and office is well-ventilated. ­‘Norovirus is spread by faecal and oral contact, but it is also spread in aerosol droplets – ­particularly if someone is vomiting near to other people,’ says Professor Openshaw.

In poorly ventilated rooms the amount of virus in the air can build up, increasing the risk of spread, especially if there are lots of infected people in the room, he adds.

The risk of airborne transmission is increased when occupants in an enclosed space are participating in energetic activity, such as exercising in a gym or sports hall, or when they are shouting, singing or talking loudly,’ says Professor Openshaw.

‘If you can open windows for short bursts of ten to 15 minutes throughout the day, it can help to improve air quality and keep virus levels down.’

Lockdowns due to Covid-19 may still be casting a long shadow, too, says Professor Easton, who believes that isolating during lockdowns and wearing masks in public may also have contributed to lowered immunity.

‘There is a possibility that over two years of not encountering flu and other respiratory infections, there’s reduced general immunity to these viruses even now.’

For those who want to avoid getting ill, it’s not too late to get a vaccination, which can offer protection in two weeks. Appointments for the NHS flu jab run until March 31, 2026.

‘It is always valuable to get a vaccine – particularly if you are elderly, because as you get older, your immune system is not as robust,’ says Professor Easton.

‘The earlier you get the vaccine the better, but getting vaccinated later is always better than not getting it at all, especially as flu often circulates through spring.’

RSV vaccinations are currently only available to people who are pregnant, aged 75 to 79, or who turned 80 after September 1, 2024 – although they may soon be offered to more vulnerable ­people. A 2024 study published in The Lancet showed that the jab was 72 per cent effective at ­preventing infection.

There isn’t a vaccine for ­norovirus. But making sure you have plenty of fibre in your diet may help boost your immune ­system and make it less likely you will fall ill in the first place.

In a study by the University of Cambridge, looking at the gut flora of more than 12,000 people in 45 countries, eating more fibre was found to support the growth of good bacteria and crowd out the bad ones to significantly reduce the risk of illness, including pneumonia, reported the journal Nature Microbiology last year.

Professor Easton explains: ‘We carry a population of bacteria in our bodies and it has become clear that the nature of this microbiome is significant in terms of our general health, which contributes to your ability to fight off infections.’

But if you have succumbed to a bug such as norovirus, it’s important to get plenty of rest and isolate until symptoms have passed.

‘I would usually recommend ­paracetamol and co-codamol, which can reduce pain and fever but don’t irritate the stomach lining,’ adds Sultan Dajani, a pharmacist based in Southampton.

‘Ibuprofen increases the risk of feeling sick as it can irritate the stomach lining and is not recommended for regular or long-term use for people over the age of 65, because it raises the chances of stomach ulcers.’

Washing your hands regularly with soap and water is essential, since the virus is spread through contact. Also be sure to replace lost fluids. 

‘Norovirus can make you lose more water than normal, especially with symptoms such as vomiting and diarrhoea, and hinder the passage of immune cells around the body,’ says Mr Dajani.

‘Eat clear vegetable or chicken soups instead of spicy food and dairy products, but avoid alcohol and caffeine, which can actually increase fluid loss.’