Covid: How Omicron symptoms differ from the Delta variant and original strain in two charts

Latest coronavirus mutation highly transmissible and resembles common cold

The Omicron variant of coronavirus has spread swiftly across the world since its discovery in South Africa and Botswana in late November and has steadily driven up daily infection numbers wherever it has been found.

Highly transmissible, the strain caused the UK to hit a pandemic-record of 218,724 new cases on 4 January but, so far, the soaring infection rate has not translated into an unsustainable level of hospitalisations and deaths.

There is still much we do not know about Omicron but its symptoms appear to be much more like that of the common cold, broadly typified by running noses, sneezing and sore throats, whereas the original strain of the virus that emerged in Wuhan, China, in late 2019 was defined by fever, coughs and an unpleasant loss of a patient’s sense of taste or smell.

A key resource for monitoring the development of the new variant in the UK has been the Zoe Covid Symptom Study, an app that encourages British sufferers to report updates on their experiences with the disease from their smartphones in the hope of better understanding it.

“The most reported symptoms of Omicron are really very much like a cold, especially in people who’ve been vaccinated,” said Dr Claire Steves, a King’s College London scientist involved with the Zoe Covid Study in a recent YouTube video analysing the latest data on the variant.

The following table records the symptoms most frequently reported to Zoe by those who have tested positive for the virus, depending on which Covid strain they have been diagnosed with.

Headaches and fatigue were often suffered by patients of “classic” Covid as well as the Delta and Omicron variants while running noses, persistent coughs and sore throats were all extremely common among all three strains.

Conversely, chest pains were found to be rare in all three manifestations of the disease while the most distinctive original symptom - loss of smell - appears to be less and less recurrent with each new mutation.

Zeroing in on Omicron more closely, this bar chart gives the most common symptoms of the variant in order of prevalence, the number denoting what percentage of sufferers demonstrated which symptoms, with runny noses again the most frequent symptom and loss of smell and breathlessness least common, occurring in less than one in five cases.

While the Zoe Covid Symptom Study’s data does not distinguish between vaccinated and unvaccinated participants, 90.5 per cent of UK citizens aged over 12 had had a jab as of Friday 14 January, 83.1 per cent were doubled-jabbed and 62.7 per cent had had a booster shot, according to the UK government’s figures.

On the importance of getting a vaccine to fend off Omicron, Christina Marriott, chief executive of the Royal Society for Public Health has previously said: “Growing evidence shows that people who’ve received two doses of the vaccine typically present with less severe symptoms, such as headache, runny nose, sneezing, sore throat and loss of smell.

“It’s important for people who’ve been fully vaccinated to stay vigilant for cold-like symptoms and get tested if they’re living or working around people who are at greater risk from the disease.”