On Friday, researchers in the UK reported that the Omicron variant of SARS-COV-2 (COVID-19) has a lower risk of hospitalisation and a shorter duration in the vaccinated population than previous variants, including Delta.
King’s College London and ZOE COVID Study scientists studied the symptoms of 62,002 vaccinated individuals to conclude that those infected with Omicron are more likely to have a sore throat and less likely to experience loss of smell compared to Delta.
The findings, published in ‘The Lancet’ this week, show the duration of symptoms were also significantly shorter for Omicron compared to the Delta variant – 6.87 days versus 8.89 days, respectively – and participants were less likely to be hospitalised.
“Although there is still a wide range of duration and severity of symptoms with Omicron, for vaccinated individuals, we find on average a shorter duration of symptoms. This suggests that the incubation time and period of infectiousness for Omicron may also be shorter,” said Professor Ana Valdes, Honorary Professor at King’s College London.
The researchers note that symptoms associated with an Omicron infection have less involvement of the lungs and do not last as long in vaccinated people.
The most striking difference between variants was the difference in loss of sense of smell, a common symptom of earlier variants – appearing in 52.7 per cent of Delta cases, only arising in under 20 per cent of Omicron cases and often days later.
The two symptoms that were consistently more prevalent among Omicron than Delta cases, regardless of vaccination status, were a sore throat and hoarse voice. Moreover, many debilitating symptoms, such as brain fog, eye burning, dizziness, fever, and headaches, though still occurring, were all significantly less prevalent in Omicron cases.
The UK’s National Health Service (NHS) had added further symptoms to watch out for, including shortness of breath; feeling tired or exhausted; aching body; headache; sore throat; blocked or runny nose; loss of appetite; diarrhoea; and feeling sick or being sick