The study concluded that those who had Omicron were less likely to be hospitalized and lose their sense of smell compared to people with Delta. Symptoms do not tend to last as long in vaccinated people with the current predominant variant as in people with Delta at 6.87 days versus 8.89 days. The findings support previous studies suggesting that the incubation time and infectivity period for Omicron are shorter than for previous COVID strains. Research has shown that olfactory loss occurs in 52.7% of Delta cases, while it occurs in less than 20% of Omicron cases – the largest difference between the two. However, the two symptoms that persisted in both variants, regardless of the vaccination status, were sore throat and hoarse voice. Some of the most debilitating symptoms, such as brain fog, burning eyes, dizziness, fever and headaches, were significantly less common in Omicron cases, according to researchers. Dr Cristina Menni of King’s College London said: “We are seeing a different clinical picture in people who have been infected with Omicron compared to Delta. “As we move even further away from the average patient with ‘basic’ UK government symptoms such as fever, persistent cough, loss of sense of smell, our results show a different selection of symptoms that may indicate infection. “In order to protect others, it is still important to isolate yourself for five days as soon as you see symptoms.” Use the Chrome browser for a more accessible video player 2:18 COVID continues to cause chaos Professor Ana Valdes, an honorary professor at King’s College London, said: “Although there is still a wide range of duration and severity of symptoms with Omicron, for vaccinated people we find an average shorter duration of symptoms. “This suggests that the incubation time and infectivity period for Omicron may also be shorter.” For the study, researchers from King’s College London and scientists from Zoe studied the symptoms of 62,002 vaccinated participants in the UK from the Zoe Covid Study App tested positive between 1 June last year and 27 November 27 when Delta was sovereign, and from 22 December 2021 to 17 January this year when Omicron was dominant. The findings will be presented at the European Conference on Clinical Microbiology & Infectious Diseases (ECCMID) this month in Lisbon.
