After arriving in the UK in December 2021, Omicron quickly became the dominant variant of coronavirus - and now scientists have shared two early signs that suggest you may have it.
Covid can impact people very differently with different symptoms and varying in severity, with some people who test positive experiencing no symptoms at all.
The jab protects against the more serious risks of Covid, but even those who are fully vaccinated can have symptoms, such as a sore throat and a headache.
Experts have now identified two symptoms that people may not traditionally associate with Covid - fatigue and dizziness or fainting.
Fatigue is more than just feeling tired. It is feeling pain in your body, sore and weak muscles, headaches, blurred vision and possible even a loss of appetite.
A Web MD poll between December 23 and January 4 found that 40% of women reported they struggled with fatigue while it hit one third of men.
It is believed Omicron could trigger fainting, according to a new report in Germany when Berlin doctors noticed a 35-year-old patient was having recurring fainting spells.
Ärztezeitung the German newspaper reported how doctors spotted a "clear connection" between the fainting and the virus.
Alongside the less well-known symptoms, a new study has identified eight key symptoms of the virus.
Researchers in Norway did a study of 111 people who attended a party in November 2021 where there was an Omicron outbreak, reports the Independent.
Out of that group 66 people tested positive for Covid, and a further 15 people have possible coronavirus.
In that group of 111 people, 89% had got two doses of the mRNA vaccine, while none had been for their booster jab.
The eight key symptoms identified in the group were cough, runny nose, fatigue, sore throat, headache, muscle pain, fever and sneezing.
Sneezing and a fever were the least common symptoms in those who had been fully vaccinated.
Nausea has also been added to the list of symptoms for the Omicron variant.
