We see cases of flu, RSV, COVID-19 and norovirus throughout the year, but in winter they circulate at the same time and can reach high levels.
We also track other respiratory viruses – rhinovirus, adenovirus, human metapneumovirus (hMPV) and parainfluenza – that can also peak over the autumn and winter months.
Flu, COVID-19 and RSV have vaccines, which are offered to different vulnerable groups.
The following is an explainer of important information about these winter infections; their signs and symptoms, and information on who is eligible for vaccination.
RSV
Respiratory syncytial virus (RSV) is a major respiratory virus that is common over the winter period, typically November to February, and can spread through coughs and sneezes.
Symptoms include cough, wheezing, shortness of breath, tiredness and fever.
While the symptoms are mild for many, RSV can cause bronchiolitis in infants, which can make it difficult for them to breathe and feed. You may see your baby experiencing fast or noisy breathing and being unsettled or difficult to comfort. This accounts for approximately 20,000 hospitalisations annually in children aged under 1.
RSV can also be severe in older adults, causing pneumonia and flare-ups of existing lung disease and other long-term conditions. It causes around 9,000 hospitalisations in those aged 75 and over in the UK each year.
An NHS vaccine has been introduced for pregnant women, to protect babies once they are born, and for those aged 75 to 79 years. It hasn’t been recommended for those age 80 or older because there were too few people of that age in the clinical trials to be sure of protection.
If received during pregnancy, the vaccine reduces the risk of severe bronchiolitis by 70% in the first six months of a baby’s life.
Flu
Flu is a viral infection affecting the nose, throat, and lungs, mostly during the winter months. It is far worse than an ordinary cold, which usually causes a runny nose, sneezing, watery eyes and throat irritation. Symptoms of a cold usually occur gradually without causing a fever or body aches, which usually occur with flu.
Flu can lead to serious illness, especially in children, with more than 8,000 hospitalisations last winter. Older people, those with a weakened immune system, and people with long-term health conditions are at higher risk. Over the past 2 winters, at least 18,000 deaths were associated with flu.
For those who took up the offer, last year’s flu vaccine had a significant impact on reducing severe illness, with a 30% reduction in the number of those aged 65 and over being hospitalised, and a 54% reduction in those aged between 2 and 17 years.
Many people are eligible for the flu vaccine including:
- Everyone aged 65 years and over,
- Those aged between 6 months and 65 with certain medical conditions.
- All pregnant women, to protect both themselves, their pregnancy and their newborn.
- All children aged 2 and 3 years via their GP and school children (reception to year 11) are offered a nasal spray vaccine through school immunisation teams.
COVID-19
While for most people COVID-19 is not as severe as during the early years of the pandemic, the virus is still causing severe illness, hospitalisations, and deaths – particularly among those with a weakened immune system and certain long-term health conditions, as well as older people.
It is normal and expected for viruses to genetically change over time and the new COVID-19 variants, much like previous variants, can spread easily through droplets released when an infected person coughs, sneezes or speaks. The autumn COVID-19 vaccines are our best defence against serious illness.
We have seen COVID-19 symptoms change over time. Today, many people now experience cold-like symptoms but some will also experience fever or chills, continuous cough, shortness of breath, tiredness, body aches, headache, sore throat, blocked nose, loss of appetite, nausea, diarrhoea, or change in sense of taste or smell.
People aged 65 and over, living in a care home for older adults, or in a clinical risk group aged over 6 months, is eligible for a COVID-19 vaccine.
Norovirus
Norovirus, also called the "winter vomiting bug", is a viral stomach bug that causes vomiting and diarrhoea. It can be very unpleasant, but usually goes away in about 2 days. This season we are experiencing the highest number of norovirus cases since our current reporting system began.
The main symptoms of norovirus are feeling sick (nausea), diarrhoea and being sick (vomiting). You may also have a high temperature, headache and aching arms and legs.
The symptoms start suddenly within 1 to 2 days of being infected and you can usually treat yourself or your child at home. The most important thing is to rest and have lots of fluids to avoid dehydration. You will usually start to feel better in 2 to 3 days.
Vulnerable groups, such as the very young, elderly or immunocompromised people, are more at risk of severe or prolonged illness and may need to seek medical treatment.
It is very important to stay off school or work until you have not been sick or had diarrhoea for at least 2 days. You also should not prepare food for others during that period as this is when you're most infectious. You should also not visit hospitals or care homes during this time.
Rhinovirus (also known as the ‘common cold’)
Rhinovirus causes what we know as the common cold. Cold symptoms come on gradually over 2 to 3 days.
The main symptoms include a blocked or runny nose, sneezing, a sore throat, a hoarse voice, a cough, feeling tired and unwell. You may also have a high temperature, aching muscles, a loss of taste and smell and a feeling of pressure in your ears and face.
Symptoms of a cold can last longer in young children. They may also be irritable, have difficulty feeding and sleeping, breathe through their mouth, and get sick after coughing.
You can get more information on telling the difference between colds and flu via the NHS website.
Adenovirus, parainfluenza and human metapneumovirus (hMPV)
These 3 viruses cause a wide range of symptoms similar to those of a cold.
Parainfluenza viruses are common causes of respiratory infections in infants, young children, older adults, and people with weakened immune systems.
Adenoviruses and hMPV typically cause mild, cold-like illnesses in people of all ages. They are seen throughout the year, but can spread more easily in winter.
Tracking these illnesses
You can see our surveillance reports published each week which track these viruses, plus flu and COVID-19 here.