The main symptoms of Omicron variant COVID-19 may differ from symptoms that were common at the start of the pandemic. Omicron may also be less severe than the Delta variant, according to a study in the UK.
People with Omicron often report sore throats and a hoarse voice, which weren’t as prevalent in Delta cases, according to a Zoe Health study. This is true for both vaccinated and unvaccinated patients.
People who contracted the Omicron variant were less likely to be hospitalized than those who had the Delta variant, Zoe Health said in a press release about the study. Symptoms also lasted for shorter periods – an average of 6.87 days, compared to 8.89 days.
Earlierthe variations often caused people to lose their sense of smell. The study found that symptoms appeared in less than 20% of cases and often several days after the onset of the first symptoms. Other serious symptoms that were prevalent – such as fever, headache, brain fog and eye pain – are less common in Omicron cases. However, they can still occur.
The Zoe Health study, which was supported by grants from the UK Department of Health and Social Care, tested vaccinated people in the UK. They tested participants between June 1 and November 27, 2021 – when the Delta variant was dominant – and between December 20, 2021 and January 17, 2022 – when the Omicron variant was dominant.
The study collected 62,002 positive tests and examined the symptoms of these patients. In addition to a difference in the duration and types of symptoms between the two variants, the researchers said that Omicron is found much less frequently in the lower respiratory tract. This is where the infection can cause more severe symptoms, potentially sending people to hospital.
They also found that Omicron symptoms did not last as long in vaccinated people.
Delta is better at infecting lung cells than Omicron, according to the study. And while Omicron appears to be much more transmissible than previous variants, this variant affects fewer organs than Delta, according to other studies, according to Zoe Health.
The Omicron sub-variant that prevailed in late 2021 and early 2022 was labeled BA.1. There are now subvariants of Omicron, labeled BA.4 and BA.5, that seem to cause loss of smell or taste again, Dr. Celine Gounder told CBS News.
A similar study from Imperial College London also found that there were fewer reports of loss of smell and taste for the Omicron variant. However, the study, which has not yet been peer reviewed, found that there were more cases of cold and flu symptoms.
The study used data from REACT-1, a widespread UK survey that collected home COVID-19 tests from around 1.5 million participants between 2020 and 2022, and analyzed how symptoms differed between variants and subvariants.
Although the newer variants like Omicron are perceived to be milder, the BA.2 subvariant of Omicron was associated with reporting more symptoms, with greater disruption of daily activities, than the subvariant BA.1 from Omicron.