The virus causing COVID has evolved over the past few months, affecting people who have contracted it in different ways.

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If at the beginning the Delta caused a loss of smell, taste, fever and breathing difficulties, the picture is completely different with the new variants of the COVID, particular Omicron which hit very hard during the last holiday season.

According to data compiled through the Zoe Health data application, which allows users to transmit their medical data for research purposes, sore throat and hoarse voice are the main symptoms linked to Omicron and sub-variants of COVID. .

These symptoms were not as prevalent with Delta and seem to affect both vaccinated and unvaccinated people equally.

In addition, people with Omicron are less likely to be hospitalized, and their symptoms last less long, averaging 6.87 days with Omicron, compared to 8.89 days for Delta.

Other severe symptoms were prevalent such as fever, headache, foggy feeling and eye pain are less common in Omicron cases. However, they can still occur.

The study which was supported by grants from the UK Government's Department of Health and Social Care tested people in the UK who had been vaccinated. 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 Omicron took over.

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.

BA.4 and BA.5 cause loss of smell

The Omicron sub-variant that prevailed in late 2021 and early 2022 was labeled BA.1. There are now sub-variants of Omicron, labeled BA.4 and BA.5, that seem to cause loss of smell or taste again, Dr. Celine Gounder told CBS News.

Although it seems confirmed that newer variants like Omicron are more 'mild', the BA.2 subvariant of Omicron was associated with more symptoms, and greater disruption of daily activities than the BA subvariant. 1 from Omicron.

New research should make it possible to draw a more precise portrait of the BA.4 and BA.5 variants that are currently almost dominant in Quebec.