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Covid-19 symptoms last less in patients infected with the Omicron variant than its Delta predecessor, at least when they are vaccinated, shows a study published Friday in The Lancet. Omicron also causes significantly less loss of smell.
To assess the differences in symptoms between Delta, largely dominant for part of 2021, and Omicron, which has supplanted it since the end of the year, British researchers studied the testimonies given by 63,000 patients, all of whom had already been vaccinated before their infection.
Symptoms lasted, on average, 8.3 days with Omicron in people who didn’t have a booster, compared to 9.6 for Delta. The difference is even more marked in the event of a prior vaccination booster: 4.4 days of symptoms with Omicron once morest 7.7 with Delta.
The study, which is to be presented soon at the European Congress of Clinical Microbiology and Infectious Diseases, also looked at the details of the symptoms.
Sore throat
Only 17% of patients infected with Omicron lost their sense of smell compared to 53% with Delta. Conversely, sore throats were much more frequent with Omicron.
The study also confirms the lesser danger of Omicron. This is already well established, but there are still doubts as to whether this variant is, in itself, less violent or if it causes fewer hospitalizations and deaths, because the population is better vaccinated than once morest its predecessors. .
These two factors probably come into play, but this work supports the hypothesis of less intrinsic danger. While the patients studied were all vaccinated, the risk of hospitalization is reduced by a quarter with Omicron compared to Delta.
This study also covers a period too old to say whether BA2, a sub-variant of Omicron that has been booming since the beginning of the year, presents clinical differences with BA1, its hitherto dominant version. But “the data recently collected by the application does not show different symptoms,” researcher Cristina Menni, who is one of the authors of the study, told AFP.
