The much-feared “winter vomiting disease,” commonly known as norovirus, is once again spreading rapidly across the United States.

Norovirus is an extremely contagious stomach virus that triggers sudden and intense episodes of vomiting and diarrhea. Anyone who has had it knows how abruptly it strikes. You can feel normal one moment and then find yourself completely incapacitated by stomach distress the next. With the holiday season nearing and people gathering indoors, norovirus infections are climbing nationwide.

Also Read: Think It’s Just Flu Or A Cold? This Cough Could Actually Be Covid

Winter Vomiting Disease In The US

Data from WastewaterSCAN, a program that tracks disease levels through municipal wastewater, shows that norovirus activity is currently classified as “high” across the U.S., with a sharp rise over the past three weeks. Marlene Wolfe, Ph.D., a professor at Emory University and director of WastewaterSCAN, told TODAY.com that the upward trend is clear and concerning.

At present, the highest levels are being recorded in the Midwest, the South, and the Northeast. States reporting notable spikes include Alabama, Connecticut, Florida, Indiana, Massachusetts, and Michigan.

In Bedford, Massachusetts, an elementary school shut down for two days this week after more than 130 students were absent with stomach-related symptoms, prompting officials to suspect a norovirus outbreak, according to NBC10 Boston. Cruise ships are also seeing a rise in outbreaks, with norovirus spreading quickly among passengers at sea.

This year’s increase appears to be arriving slightly earlier than usual and is likely linked to a newer strain of the virus, which drove a particularly severe 2024–2025 season. Last winter, norovirus cases reached their highest levels in more than a decade.

Norovirus GII.17 Variant

Since the early 2000s, most norovirus outbreaks have been linked to a strain known as GII.4, according to previous reports from NBC News. Roughly a decade ago, another strain called GII.17 first appeared in Asia and has expanded significantly in recent years. During the 2024–2025 season, GII.17 accounted for 75 percent of norovirus outbreaks in the U.S., compared with less than 10 percent in 2023, a CDC study found.

“When a new strain appears, it can spread very quickly,” Roberts says. “That is exactly what happened last year.”

Experts are unsure whether GII.17 spreads more easily than GII.4. However, they say more people may be vulnerable because they lack immunity to this newer variant.

Infection with norovirus does offer some level of immune protection, but it is incomplete, Schaffner explains.

“We do not know how long that immunity lasts,” Roberts says. “And it likely does not protect you against a different strain.”

If a large portion of the population is susceptible, the virus may have more opportunities to circulate widely. How this season unfolds remains uncertain.

Winter Vomiting Disease: Norovirus Symptoms

“This is not a subtle illness,” Roberts says. Symptoms typically appear suddenly, usually within 12 to 48 hours of exposure.

Some common signs of norovirus are:

• Vomiting
• Diarrhea
• Nausea
• Stomach pain and cramping

Some people may also experience a mild fever, chills, or headache, according to the CDC.

“The good news is that it does not usually last long,” Schaffner says. “Most people feel terrible for about two days, then recover.”

In most cases, symptoms resolve on their own within one to three days.

However, the virus can cause significant fluid loss, increasing the risk of dehydration. Certain groups face a higher risk of severe illness and hospitalization, including children under 5 and adults over 85.

Medical care should be sought if symptoms continue beyond a few days, if there is blood in vomit or stool, or if signs of dehydration appear, such as dizziness or dark urine, according to the Cleveland Clinic.

Winter Vomiting Disease: Norovirus Treatment

There is no medication that directly treats norovirus. Care focuses on managing symptoms through rest and fluid replacement, Roberts says. Drinks that replenish electrolytes can be helpful.

“It is better to take small sips,” Schaffner advises. “Drinking too much at once can make vomiting worse.”

In more serious cases, intravenous fluids may be necessary to prevent dehydration. Anyone with concerns should contact a health care provider, Schaffner adds.

There is currently no approved vaccine for norovirus, though a Moderna vaccine candidate is undergoing phase 3 clinical trials.

Winter Vomiting Disease: How Does Norovirus Spread?

“It is an especially troublesome virus because it spreads so easily and in so many ways,” Schaffner says. An infected person can release billions of virus particles through vomit or stool. “It only takes one to ten particles to cause an infection,” he notes. Norovirus usually spreads through the fecal-oral route, Roberts explains, when virus particles from feces make their way into the mouth, often via unwashed hands.

Some common ways how the virus spread are:

• Close contact with someone who is infected
• Touching contaminated surfaces and then touching the mouth
• Eating or drinking contaminated food or beverages
• Breathing in or swallowing particles released during vomiting

People are most contagious from the time symptoms begin until a few days after they feel better. However, the virus can continue to be shed in stool for up to two weeks after recovery, Roberts says.

Norovirus can survive on surfaces, objects, and foods for extended periods. Foods frequently linked to outbreaks include leafy greens, fresh produce, and shellfish, according to the CDC.

Does Hand Sanitizer Kill Norovirus?

Norovirus is especially difficult to eliminate. Alcohol-based hand sanitizers and cleaners are largely ineffective because the virus has a tough outer shell that alcohol cannot break down. “The only way to remove it from your hands is to physically wash it away,” Schaffner says. “Soap and water lift the virus off the skin and rinse it down the drain.”

One particularly vulnerable group across the UK is being strongly advised to receive up to three vaccines this season. This winter has seen a sharp rise in seasonal viruses, with the NHS warning that hospitals and ambulance services are under significant pressure due to higher demand.

This surge is largely driven by the H3N2 flu strain, known as subclade K, which is currently circulating at ‘medium’ levels but with increased activity. The UK Health Security Agency reports that flu-related hospital admissions have climbed to 7.79% per 100,000, up from 4.78% per 100,000 the previous week.

While common winter viruses such as flu, RSV, and whooping cough can cause uncomfortable symptoms for most people, certain groups face a higher risk of serious complications. These include children, older adults, people with weakened immune systems, and pregnant women.

Why You Should Get Vaccinated While Pregnant

Flu shots are highly effective at protecting both mothers and their babies, as the body responds differently to infections during pregnancy. NHS guidance notes that pregnant women are more susceptible to complications from viral infections, particularly in the later stages of pregnancy.

Infants are also at a higher risk of severe illness if exposed to viruses, which can sometimes result in mothers and babies requiring intensive care. Additionally, infections like flu can increase the risk of premature birth or low birth weight, which may raise the chance of stillbirth or neonatal death.

Posting on X, the UK Health Security Agency said that pregnant women are entitled to vaccinations against flu, RSV, and whooping cough, and advised them to consult their midwife, GP, or local pharmacist for guidance on getting vaccinated.

How Vaccines Protect Pregnant Mothers And Their Babies

Vaccination during pregnancy passes protective antibodies to the baby, giving them similar levels of defence against serious illness in the first weeks of life. This applies to vaccines for flu, whooping cough, and RSV, helping shield both mother and newborn.

Vaccines Pregnant Women Aren't Advised To Get

Pregnant women are generally advised to avoid vaccines that contain a live version of a virus, as these could theoretically infect the unborn child. However, evidence shows live vaccines do not typically cause birth defects.

The main exception is when the risk of infection is higher than the potential risk from the vaccine itself. Examples of live vaccines include:

• Yellow fever
• Measles, mumps, and rubella (MMR)
• Tuberculosis (BCG vaccine)

Is It Safe To Get A Flu Shot During Pregnancy?

The American College of Obstetricians and Gynecologists advises that anyone who is pregnant during flu season should receive the flu shot, regardless of which trimester they are in.

A flu vaccine during pregnancy can help in several ways:

Lower the risk of flu-related illness during pregnancy

Pregnancy changes how the immune system, heart, and lungs function, which can make flu infections more severe. A flu shot reduces the chance of catching the flu and lowers the risk of needing hospital care if you do get sick.

Reduce risks to the developing baby

Getting the flu, especially early in pregnancy, may increase the risk of certain health problems in the unborn baby. Flu infection has also been linked to a higher chance of birth-related complications.

Protect the baby after delivery

Newborns are more likely to become seriously ill from the flu, but they cannot be vaccinated until they are six months old. Antibodies produced after a flu shot during pregnancy cross the placenta and are also found in breast milk, helping protect the baby in the first months of life.

When getting vaccinated, pregnant women should choose the flu shot, not the nasal spray. The injection uses an inactive virus and is safe at any stage of pregnancy. The nasal spray contains a live virus and is not recommended for pregnant women.

The NHS has released an alert for people taking a widely prescribed medication used by millions across the UK. Diabetes rates are at an all-time high, with the latest data showing more than 5.8 million people currently living with the condition.

Diabetes UK estimates that around 4.6 million people have already been diagnosed. At the same time, close to 1.3 million people are believed to have Type 2 diabetes without knowing it. The number of cases continues to climb, with figures from 2023–24 showing an increase of 185,034 compared to the previous year.

What Is Metformin Used For?

Metformin is most commonly prescribed for people with Type 2 diabetes. It helps lower and stabilise blood sugar levels and is often the first medicine recommended, alongside changes to diet and physical activity. According to Healthline, it is not used to treat Type 1 diabetes.

What Is Diabetes?

Diabetes is a condition where blood sugar levels become too high. There are three main types. Type 1 diabetes cannot be prevented and is usually diagnosed in childhood. Type 2 diabetes can sometimes be prevented or managed through lifestyle changes such as healthier eating, regular exercise, and weight loss. Gestational diabetes develops during pregnancy. People with Type 1 diabetes need insulin for life, while many with Type 2 or gestational diabetes may manage their condition through lifestyle changes and, in some cases, medication.

Metformin Warning: NHS Issues Alert

The NHS says that people taking metformin should be aware of certain symptoms. Information published on the NHS website lists six common side effects of the medicine. These include:

• feeling sick
• being sick
• diarrhoea
• stomach pain
• loss of appetite
• a metallic taste in the mouth

The NHS also notes that metformin can increase the risk of vitamin B12 deficiency. Some people may experience low blood sugar, but this usually happens only when metformin is taken alongside other diabetes medicines such as insulin or gliclazide.

However, the NHS warns that there are other, more serious side effects. In two situations, patients are advised to contact their GP “straight away,” while one requires calling 999 “now.”

Metformin Serious Side Effects

According to the NHS, serious side effects are uncommon and affect fewer than 1 in 10,000 people. However, medical help should be sought immediately by calling a doctor or dialling 111 if:

you feel generally unwell with extreme tiredness, fast or shallow breathing, feeling cold, and a slow heartbeat

the whites of your eyes turn yellow, or your skin becomes yellow, which may be harder to notice on brown or black skin, as this can indicate liver problems

Metformin Serious Allergic Reaction

In rare cases, metformin can cause a severe allergic reaction known as anaphylaxis. The NHS advises calling 999 immediately if:

• your lips, mouth, throat, or tongue suddenly swell
• you are breathing very quickly or struggling to breathe, including wheezing or feeling as though you are choking
• your throat feels tight or you have difficulty swallowing
• your skin, tongue, or lips turn blue, grey, or pale, which may be easier to spot on the palms or soles in people with darker skin
• you suddenly feel confused, very drowsy, or dizzy
• someone collapses and cannot be woken
• a child becomes limp, floppy, or unusually unresponsive, with difficulty holding up their head or focusing

The NHS adds that you or the affected person may also develop a rash that is swollen, raised, itchy, blistered, or peeling. These signs point to a serious allergic reaction and may require urgent hospital treatment.

The public is being advised to limit close contact with others if they experience flu or Covid symptoms, as the NHS braces for a challenging winter ahead. A mutated, or “drifted”, version of the H3N2 flu strain is fuelling a faster and earlier rise in infections and hospital admissions in 2025. Dr Conall Watson, Consultant Epidemiologist at the UK Health Security Agency, has urged those who are eligible to get vaccinated at the earliest.

He said there are also everyday precautions that can help protect others, especially during the festive season. “If you have symptoms of flu or Covid-19, such as a high temperature, cough, or feeling tired or achy, you should try to reduce contact with other people, particularly those who are more vulnerable. Regular handwashing and good ventilation indoors both make a difference. If you need to go out while unwell, wearing a face covering is worth considering,” he added.

This guidance becomes even more important in the run-up to Christmas, when families tend to gather and older relatives, who face a higher risk of serious illness, are often present.

Flu Symptoms 2025: Less Obvious Symptoms People Often Miss

While many flu symptoms are widely recognised, some are less commonly associated with the illness. The NHS lists ten typical flu symptoms, which often appear suddenly.

Among these, three signs that people may overlook are trouble sleeping, a reduced appetite, and feeling unusually tired or drained. During the busy weeks leading up to Christmas, these symptoms can easily be dismissed as stress or exhaustion rather than flu.

Flu Symptoms 2025: Full List of Common NHS-Listed Signs

The remaining seven symptoms listed by the NHS include a sudden high temperature, body aches, a dry cough, sore throat, headache, diarrhoea or stomach pain, and feeling sick or being sick.

At the same time, the NHS is dealing with added pressure from a surge in winter viruses alongside a five-day strike by resident doctors, previously known as junior doctors. Health leaders and the Government have called on doctors to withdraw the strike, which ministers have described as reckless and irresponsible given the strain on services.

Flu Symptoms 2025: NHS Under Pressure as Winter Challenges Mount

Home Secretary Shabana Mahmood, as per The Independent, said that strikes within the NHS “undoubtedly” put lives at risk. Speaking to Sky News’ Sunday Morning With Trevor Phillips, she said, “We want to ensure the NHS is supported through a difficult winter and this flu outbreak we are currently seeing. It is important that everyone understands what is at stake.”

She also pointed to a difference between the position taken by resident doctors’ leadership and the views of individual doctors, noting that the situation remains sensitive as the NHS navigates one of its most demanding winter periods.

Flu Symptoms 2025: Who Can Still Get Vaccinated?

The NHS provides the flu vaccine free of charge to groups considered most at risk of serious illness. This includes people aged 65 and above, those with certain long-term health conditions, and pregnant women, as per the official NHS website.

The offer also extends to care home residents, carers who look after older or disabled individuals or receive a carer’s allowance, and people living with someone who has a weakened immune system. Frontline health and social care workers are also eligible and can usually receive the vaccine through their employer.

Children are included too. A nasal spray version of the flu vaccine is offered to children aged two and three, as well as school-going children from reception through to year 11.

This is because children tend to catch and spread flu more easily. Vaccinating them not only protects their own health but also helps reduce the risk for vulnerable people around them who could become seriously ill.