Doctors are seeing rotavirus cases earlier and more frequently this year, with the latest data from the US Centers for Disease Control and Prevention showing that almost 8 in every 100 people tested now have the virus. While that figure is only slightly higher than last year’s rate of 7 per cent, the real concern is timing: cases began rising in January, weeks earlier than the usual spring peak, meaning more children are being exposed over a longer period. UK health officials are watching the situation closely, mindful that the same virus – the leading cause of severe gastroenteritis in British infants – could follow a similar pattern if vaccination rates falter.
The current surge
Rotavirus is typically a springtime illness in the United States, with cases building through the winter and hitting their highest point around April or May before fading in summer. This year, according to CDC surveillance, around 3 per cent of tests were positive in January – when normally only about 1 per cent would be – and that rate is now peaking at nearly 8 per cent. Independent monitoring of community sewage, which tracks the spread of germs, has found that levels of the virus in wastewater have risen by roughly 40 per cent since February. Taken together, the data tell doctors that rotavirus is circulating more widely and persisting for longer than usual.
What is rotavirus and why is it dangerous?
Rotavirus, first identified in 1973, attacks the gastrointestinal system – the stomach and intestines. It is highly contagious and spreads primarily through the faecal-oral route: germs from an infected person’s stool get onto hands or surfaces and are then ingested. The virus can also be transmitted via airborne droplets from coughing and sneezing, through contaminated food or water, and by touching objects such as toys, door handles or furniture. Asymptomatic carriers are common, meaning people can spread the virus without showing any symptoms.
The illness causes sudden, severe watery diarrhoea, vomiting and fever, often accompanied by stomach cramps and loss of appetite. Symptoms typically last three to nine days. The greatest danger, especially for infants and young children, is rapid dehydration. Signs of dehydration in babies include fewer wet nappies, a dry mouth and throat, sunken eyes, few or no tears when crying, unusual sleepiness or fussiness, lethargy, rapid breathing and a fast heartbeat. Without treatment, severe dehydration can lead to shock, cardiac arrhythmia and, in rare cases, death. There is no medicine to cure rotavirus; doctors can only provide fluids and monitor for dehydration, and babies who lose too much fluid may need hospital care.
Most children under five who are not vaccinated will contract rotavirus at some point. The virus is most common in infants aged six months to two years, but it can infect people of all ages. Older children and adults usually experience milder infections, while those with weakened immune systems and people over 65 are at risk of severe illness. In the UK, rotavirus is the most common cause of gastroenteritis in infants and young children, accounting for around half of all cases in this age group before the vaccine was introduced. Estimates from the pre-vaccine era suggest that every year in England and Wales about 12,700 children were hospitalised with rotavirus gastroenteritis – representing 54 per cent of all hospital admissions for intestinal infectious disease – and that three to four children died each year from dehydration caused by the virus.
A safe and effective vaccine
Safe and effective rotavirus vaccines have been available in the United States since 2006. An earlier vaccine was approved but withdrawn the following year after doctors discovered it carried a very rare risk of a serious bowel problem. The vaccines used today are different: studies involving more than 70,000 babies have confirmed they are safe and work well. In the US, before vaccination began, rotavirus caused more than 400,000 medical visits each year, including 200,000 emergency room visits, 70,000 hospitalisations and between 20 and 60 deaths. Since the vaccine’s introduction, hospitalisations have fallen by 80 per cent and emergency room visits by 57 per cent, and the vaccine now prevents an estimated 40,000 to 50,000 infant hospitalisations annually.
In the United Kingdom, the rotavirus vaccine (Rotarix®) was added to the routine childhood immunisation schedule in July 2013. Babies are offered two oral doses – a liquid squirted into the mouth – at eight weeks and twelve weeks of age, alongside their other primary vaccinations. The first dose can be given up to 15 weeks of age and the second up to 24 weeks if a dose is missed. The vaccine is highly effective: it prevents rotavirus infection in about eight out of ten babies who receive it and significantly reduces the risk of severe disease, hospital visits and dehydration. Since its introduction, reported cases of rotavirus in the UK have fallen by more than 70 per cent.
There are some contraindications. The vaccine should not be given to babies with Severe Combined Immunodeficiency (SCID), those whose mothers received immune-compromising treatments during pregnancy or breastfeeding, or those who have had a severe reaction to a previous dose or vaccine ingredients. It should also be postponed if a baby has a fever, diarrhoea or is vomiting on the day of the appointment. In very rare cases – around one to six per 100,000 first doses – the vaccine is associated with a small increased risk of intussusception, a type of bowel blockage that occurs most often in babies older than three months. Symptoms include severe abdominal pain, vomiting and possibly blood in the stool. Experts stress that this risk is extremely small compared with the dangers of rotavirus infection itself.
Declining vaccination rates and their impact
Vaccination coverage for rotavirus in the United States has been dropping. In 2018, 77 per cent of children had received the full vaccine series by eight months of age; by 2024 that figure had fallen to 74 per cent. That may not sound like a large decline, but it leaves a growing number of infants unprotected and susceptible to infection. Epidemiologist Annette Regan, who has studied the virus, notes that rotavirus surges tend to be shorter in communities where more people are vaccinated. When vaccination rates fall, outbreaks can last longer and affect more children, particularly the very youngest who are most vulnerable to severe dehydration.
The situation has been further complicated by policy changes. In January 2026, the US Department of Health and Human Services shifted rotavirus vaccination from a universal recommendation to a decision to be made by families and their healthcare providers. Although that change was later paused by a federal judge, the uncertainty has left public health officials increasingly concerned that vaccination rates could continue to slide. In the UK, uptake has remained relatively high since the vaccine was introduced, but health experts warn that any sustained drop – whether driven by vaccine hesitancy, access issues or policy shifts – could undo the gains made over the past decade. Because rotavirus is so contagious, even a small reduction in coverage can allow the virus to spread more easily, leading to more hospitalisations and more babies suffering severe dehydration.
Proper hand-washing can reduce transmission, but the virus is extremely hardy and can survive on surfaces for long periods. The most effective protection remains vaccination. The two oral vaccines available in the US reduce the risk of severe disease in infants by 85 to 90 per cent. In the UK, the Rotarix vaccine has been shown to prevent infection in approximately 80 per cent of babies. These benefits, however, depend on most children being vaccinated. When coverage falls, the community protection that shields the youngest infants – those too young to have completed their vaccine series – begins to erode. The current early surge in America, with cases rising since January and sewage levels climbing, is a reminder that rotavirus can return quickly when immunity gaps appear. Doctors on both sides of the Atlantic are urging families to ensure their babies receive the full course of vaccine on schedule, because the health of each child depends on the protection of all.
