The subtle differences between the illnesses can sometimes be hard to spot
As winter sets in, it’s important to be aware of the various illnesses that could strike and how to tell them apart. With so many common winter bugs and viruses causing similar symptoms, it can be tricky to pinpoint exactly what’s wrong with yourself, a friend, or a family member.
Winter is prime time for diseases as people gather indoors, creating a warm breeding ground for common health issues. But with such a wide range of ailments, diagnosing the exact problem can often feel like a stab in the dark.
However, typical culprits like colds, flu, and RSV can each have unique signs that help identify which virus is causing chaos within the body. These differences may be subtle, but recognising the root cause can sometimes speed up the recovery by allowing you to tackle the issue head-on.
The UK Health Security Agency (UKHSA) has issued information ahead of the winter season, a period when certain diseases spread like wildfire from one household to another. While these viruses are always around throughout the year, their rates tend to spike during the colder months when they all circulate at once.
Here’s a breakdown of the latest differences between COVID, the flu, the common cold and the respiratory syncytial virus (RSV), as of October 2025, along with the known symptoms of each, reports the Express.
Flu
Flu is a viral infection that primarily affects the nose, throat, and lungs, predominantly during the winter months. It’s far more severe than a standard cold, with symptoms developing rapidly, including:
- 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
While Covid-19 is not as severe for most people as it was in the early stages of the pandemic, it continues to cause serious illness, hospitalisations and deaths – especially among those with weakened immune systems and those aged 75 and over. Many people experience symptoms similar to a common cold, while others may also suffer from:
- Fever or chills,
- a persistent cough,
- shortness of breath,
- fatigue,
- body aches,
- headaches,
- a sore throat,
- a blocked nose,
- loss of appetite,
- nausea,
- diarrhoea,
- or changes in taste or smell due to the latest variants.
As of October 2025, the predominant covid-19 strains circulating are the Omicron subvariants XFG, known as “Stratus,” and NB. 1.8.1, dubbed “Nimbus.” They have become the most prevalent variants circulating in the UK, as reported by officials.
These variants are being closely monitored by UK authorities and the World Health Organisation (WHO). The Stratus variant has been linked to a hoarse voice, although some experts question whether this is a reliable distinguishing symptom from other respiratory viruses.
The Nimbus variant is associated with a particularly severe or “razor blade” sore throat. Experts indicate that these variants do not seem to present a greater threat than earlier strains of covid, nor do they cause increased illness.
RSV
Respiratory syncytial virus (RSV) is another serious respiratory virus that typically spreads during the winter months, from November to February, through coughs and sneezes. Almost all children will contract this virus at least once before their second birthday.
While they’re typically not serious, some babies and adults are at a higher risk of becoming seriously ill. Most people only experience symptoms similar to a common cold, but if these progress into more severe infections, such as pneumonia or bronchiolitis, they can result in shortness of breath and an intensifying cough.
Rhinovirus
Better known as the common cold, symptoms usually develop gradually over two to three days. The primary symptoms include a blocked or runny nose, sneezing, a sore throat, a hoarse voice, a cough, and feeling tired and unwell.
Young children’s cold symptoms can last longer. They may also be irritable, have difficulty feeding and sleeping, breathe through their mouths, and get sick after coughing.
You may also experience a high temperature, muscle aches, a loss of taste and smell, and a sensation of pressure in your ears and face. Cough and cold medicines can be obtained from pharmacies or supermarkets.