Rotavirus is a viral infection that commonly leads to severe diarrhoea and vomiting in young children. Before a vaccine was introduced, it affected almost every child in the world by the age of five and around 12,700 children a year were admitted to hospital.
It is highly infectious and can cause death through severe dehydration. However, in the UK, where there is good medical care, very few children have died from rotavirus infection.
In the developing world, children are much more at risk. The World Health Organization estimated that rotavirus infections caused between 475,000 and 580,000 deaths worldwide in 2004 before vaccines were developed, mainly in developing countries.
The virus is generally spread from one person to another through the contamination of hands and surfaces with faeces (poo).
Rotavirus symptoms include severe watery diarrhoea and vomiting for three to eight days. Vomiting is often the first symptom, but other symptoms, such as mild fever and stomach cramps, are often experienced.
It is usually spread from one person to another through faeces, which can contaminate poorly washed hands and surfaces. Occasionally it can be passed on through droplets coughed or sneezed into the air.
Older children and adults can be infected without showing the usual symptoms, and this often helps rotavirus infections to be passed on in a community.
Rotavirus infection in the UK is seasonal. Before a vaccine was introduced there was usually a peak in cases between January and March.
Good hand washing and hygiene can sometimes help to stop the spread of the disease. However, because rotavirus is so infectious and difficult to stop spreading, good hygiene by itself is often not very effective at preventing the disease altogether.
There are five different types of the virus, known as A, B, C, D, and E. Type A causes 90% of infections in humans. The vaccine used in the UK gives protection against type A infections.
Although rotavirus is not often life-threatening in the UK, it caused a huge amount of illness before a vaccine was introduced in 2013. Each year in the UK:
130,000 children were so unwell with rotavirus that they needed to see their GP
36,000 children with rotavirus were taken to A&E
Around 12,700 of these were admitted to hospital, usually because of severe dehydration
It is thought that three or four children died each year in the UK as a result of rotavirus infection, and some people have given higher estimates
Death was due to severe dehydration caused by diarrhoea and vomiting
The graph below shows what has happened in the UK since the rotavirus vaccine was introduced in July 2013. In 2014, 2015 and 2016, the number of reported cases of rotavirus fell by over 70% compared to previous years. Rotavirus infections tend to peak between January and March, but in these years there was no significant peak in cases.