A new Covid strain dubbed Stratus is spreading rapidly in the UK, accounting for the largest number of cases in England. And there's one tell-tale sign that sets it apart, according to experts.

The latest strain, which has two variants - XFG and XFG.3 - was first detected in January. By June, the World Health Organization (WHO) placed XFG on its monitoring list owing to its fast growth.

By September 10, the UK Health Security Agency (UKHSA) noted a 7.6 per cent increase in coronavirus cases across England compared with the previous week, although it's unclear how many stem from the XFG variant.

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Generally, Covid symptoms tend to mirror other seasonal illnesses like the flu or a cold, including a runny nose, fever, cough and sneezing.

But a key early indicator of Stratus is a hoarse voice, which may start before more conventional Covid symptoms. This unusual early warning can easily be overlooked.

Dr Nye told the Mirror: "In most ways, it's almost identical. However, people with this version tend to get very sore throats and a hoarse voice, compared with the other more general symptoms like cough, temperature and aches.

"Illnesses always see spikes as children go back to school, as close contact and often lower personal hygiene levels mix."

Explaining what to expect from the variant, he warned: "This version is more likely to make you sick, however, as they appear to be able to avoid your immune system even if you've had it before. [This] makes prior vaccines less useful, which makes regular vaccination against the latest coronavirus even more important. Think of it like updating your phone to get the best possible experience."

Meanwhile, infectious disease expert Dr Peter Chin-Hong from the University of California, San Francisco, also cautioned that Stratus displays a "wider range of symptoms" compared to earlier variants.

Speaking to SFGATE, he explained: "There's a little bit more sore throats with some people. Particularly in those who are older, who didn't get vaccinated last year.

"It's more transmissible, so we expect that a lot of people will get it. Particularly with kids going back to school, a sniffle is likely going to be Covid."

If you're wondering if you've got the flu, a cold or the new Covid variant, here are the symptoms to look out for. Please note that symptoms vary from person to person.

These are the recognised symptoms of Covid that people are advised to look out for, as outlined by the NHS. But experts have also warned, as above, that patients with Stratus are experiencing a hoarse voice.

• a high temperature or shivering (chills) – a high temperature means you feel hot to touch on your chest or back (you do not need to measure your temperature)
• a new, continuous cough – this means coughing a lot for more than an hour, or 3 or more coughing episodes in 24 hours
• a loss or change to your sense of smell or taste
• shortness of breath
• feeling tired or exhausted
• an aching body
• a headache
• a sore throat
• a blocked or runny nose
• loss of appetite
• diarrhoea
• feeling sick or being sick

The NHS notes that these symptoms can come on "very quickly" and can consist of:

• 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

The NHS states that most people experience cold-like symptoms with an RSV infection, which typically start within a few days of getting infected. Symptoms, as outlined by the NHS, can include:

• a runny or blocked nose
• a cough
• sneezing
• tiredness
• a high temperature – signs include your back or chest feeling hotter than usual, sweatiness and shivering (chills)