Scientists are currently dissecting the new Omicron Covid variant in a bid to understand what its unusually high number of mutations will allow it to do.
The variant, which has rapidly spread from Southern African to the UK, is understood to be much more infectious than previous strains as a result of its mutations, the Wales Online reports.
And there are indications that it may make the vaccine less effective.
Go here for the latest coronavirus updates and breaking Covid-19 news
The doctor who raised the alarm on the new variant has explained unusual symptoms seen in patients found to have the Omicron variant.
Dr Angelique Coetzee spotted the variant when patients arrived at her practice in Pretoria, South Africa, with Covid symptoms that did not make sense.
She says the new variant has presented young people all with intense fatigue and a six-year-old child with the virus was found to have a high pulse rate.
She says there was no sore throat or cough, instead, patients said their throat was more scratchy and suffered a mild headache.
None of the patients had the loss of sense of taste or smell that has become a common indicator of Covid-19.
Dr Coetzee, who has been a GP for 33 years and chairs South Africaâ€™s Medical Association, said: â€œTheir symptoms were so different and so mild from those I had treated before."
Dr Coetzee raised the alarm on November 18 when four members of the same family all tested positive for Covid. All four were suffering from exhaustion.
She says most of the patients she has seen so far with the new variant are healthy men who are â€œfeeling so tired"
Anyone who has any of the common symptoms associated with Covid-19 which include a cough, fever, loss of sense of taste or smell should take a lateral flow test.
However, people should also be aware of the new symptoms that are emerging with the discovery of the new variant.
If you feel unwell you can contact your GP or call NHS 111, or visit the NHS website to get advice on the best course of action.
For the latest local news in your area direct to your inbox every day, go here to sign up to our free newsletter