People should be aware of what kind of illnesses are spreading this winter, and how to tell them apart. It can be a struggle to tell the difference when lots of common winter bugs and viruses can cause very similar problems.
Diseases take advantage of the winter months, when people spend more time indoors, creating an environment where common health problems can thrive. However, with so many different types of sickness, pinning down exactly what is wrong can sometimes be a guessing game.
However, common problems like colds, flu, and RSV all have a few things that tell you which virus is wreaking havoc inside your body. The differences can be subtle, but being able to identify the cause of the problem can sometimes lead to quicker recovery if you’re able to target the issue directly.
The UK Health Security Agency (UKHSA) has put out information ahead of the winter season, when certain diseases run rampant from household to household. Whilst these viruses do spread all year round, the colder months tend to reach high levels as they all circulate at once.
Below are the differences between covid, the flu, the common cold and the respiratory syncytial virus (RSV), including the known symptoms of each.
Flu
Flu is a viral infection affecting the nose, throat, and lungs, mostly during the winter months and will feel far worse than an ordinary cold. Some signs of the disease develop very quickly, and can include:
- a sudden high temperature
- an aching body
- feeling tired or exhausted
- a dry cough
- a sore throat
- a headache
- difficulty sleeping
- loss of appetite
- diarrhoea or tummy pain
- feeling sick and being sick
Covid-19
For most people, covid-19 is not as severe as it was during the early years of the pandemic. However, the virus is still causing severe illness, hospitalisations, and deaths – particularly among those with a weakened immune system and those 75 years old and over.
Many people experience cold-like symptoms, and 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 a change in sense of taste or smell associated with the latest variants. Some people report a hoarse voice or a particularly painful sore throat associated with the latest variants.
As of October 2025, the predominant covid-19 strains in circulation are the Omicron subvariants XFG, known as “Stratus,” and NB.1.8.1, referred to as “Nimbus.” The UK authorities and the World Health Organization (WHO) have been keeping a close watch on these variants.
Stratus is associated with a hoarse voice, though some experts question whether this is a reliable distinguishing symptom from other respiratory viruses. Nimbus is associated with a particularly severe or “razor blade” sore throat.
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. Almost all children get them at least once before they’re 2 years old.
They’re not usually serious, but some babies and adults are at a higher risk of getting seriously ill. Most people only get cold-like symptoms, but if they lead to more serious infections, like pneumonia or bronchiolitis, they can cause shortness of breath and a worsening cough.
Rhinovirus
Best known as the common cold, symptoms come on gradually over two to three days. The main symptoms include a blocked or runny nose, sneezing, a sore throat, a hoarse voice, a cough, and 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. Cough and cold medicines are available from pharmacies or supermarkets.