Symptoms of the Omicron variant of covid can be confused with the common cold, scientists have warned.
The variant, which UK authorities first became aware of in November, now accounts for 90% of all cases in London.
One symptom which differentiates the variant from the early form of the virus is the tendency to cause a hoarse voice.
READ MORE : Three countries Brits can travel to without taking a covid test
The ZOE Symptom Covid Study, the world's largest data study into the virus, said: "A hoarse voice can be an early symptom, but its pattern of presentation can vary.
"Usually, it appears in the first week of illness and builds gradually. For other people, a hoarse voice comes and goes. "
Other symptoms of the variant, which is due to mutations on the spike protein of the virus targeted by vaccines, are thought to be more similar to the common cold.
The ZOE Symptom Covid Study said the top five symptoms of the variant are a runny nose, headache, fatigue (mild or severe), sneezing and a sore throat.
Symptoms of the initial form of the Covid-19 virus are also present such as a cough, fever and a loss of smell or taste.
UK scientists became aware of the Omicron strain on November 23, after samples were uploaded to a coronavirus variant tracking website from South Africa, Hong Kong and then Botswana.
The World Health Organisation (WHO) designated it a "variant of concern" on November 26, because it has several mutations which means it is more difficult to predict how it will behave.
