Omicron symptoms may differ from those of other COVID-19 variants

Vancouver -

Early data from the U.K. has found that cold-like symptoms are more common among those infected with the Omicron variant of the novel coronavirus.

The ZOE COVID Symptoms Study, which tracks symptoms recorded from participants using a smartphone app, reported on Thursday that the top five symptoms for Omicron were runny nose, headache, fatigue, sneezing and sore throat.

The data was collected between Dec. 3 to 10 in London, where Omicron has become the dominant strain, based on over 52,000 COVID-19 tests.

• Newsletter sign-up: Get The COVID-19 Brief sent to your inbox

Unlike with other strains of the virus, symptoms of fever, cough and loss of smell were less common. The ZOE analysis found that only 50 per cent of those with Omicron had these three "classic symptoms."

Loss of appetite as well as brain fog were also commonly reported symptoms.

"Hopefully people now recognise the cold-like symptoms which appear to be the predominant feature of Omicron. These are the changes that will slow the spread of the virus," ZOE lead scientist Tim Spector said in a news release on Thursday.

These findings are also consistent with early data from the U.S. Centers for Disease Control and Prevention (CDC), which studied 43 Omicron cases from Dec. 1 to 8. The CDC found that cough, fatigue, and congestion or runny nose were the most common symptoms among the cohort, three-quarters of whom were fully vaccinated.

Similarly, Dr. Angelique Coetzee, who is the chair of the South African Medical Association and the first doctor to detect the Omicron variant, has said that fatigue was among the most common symptoms she's observed, along with headaches, body aches and "scratchy" throat.

"Most of them are seeing very, very mild symptoms and none of them so far have admitted patients to surgeries. We have been able to treat these patients conservatively at home," she told Reuters in late November.

A preliminary study from South African researchers also found that after adjusting for vaccination status, the risk of hospitalization was 29 per cent lower for the Omicron variant compared to the first wave of the virus in mid-2020.

However, experts say it's too early to say whether Omicron will be less severe in Canada.

"The long and the short of this is that some country data says that this might be a less severe disease. Other country data does not say that," Dalhousie University infectious diseases expert Dr. Lisa Barrett told CTV News Channel on Saturday.

Barrett pointed to Denmark, where data has showed that hospitalization rates appear to be on par with other variants of the virus.

A preliminary U.K. study published on Thursday also found "no evidence (for both risk of hospitalization attendance and symptom status) of Omicron having different severity from Delta" based on data collected in England between Nov. 29 and Dec. 11.

"Even if you're not in the hospital, I think businesses and other people should know you can be pretty darn sick and still not go to hospital," Barrett said.