biostudies-literatureMenni CMedical Research CouncilAlzheimer's SocietyWellcome Trust1618-1624https://www.ebi.ac.uk/biostudies/studies/S-EPMC8989396biostudies-literatureUnknown399(10335)<h4>Background</h4>The SARS-CoV-2 variant of concern, omicron, appears to be less severe than delta. We aim to quantify the differences in symptom prevalence, risk of hospital admission, and symptom duration among the vaccinated population.<h4>Methods</h4>In this prospective longitudinal observational study, we collected data from participants who were self-reporting test results and symptoms in the ZOE COVID app (previously known as the COVID Symptoms Study App). Eligible participants were aged 16-99 years, based in the UK, with a body-mass index between 15 and 55 kg/m², had received at least two doses of any SARS-CoV-2 vaccine, were symptomatic, and logged a positive symptomatic PCR or lateral flow result for SARS-CoV-2 during the study period. The primary outcome was the likeLancet (London, England)Symptom prevalence, duration, and risk of hospital admission in individuals infected with SARS-CoV-2 during periods of omicron and delta variant dominance: a prospective observational study from the ZOE COVID Study.PMC8989396215010/Z/18/ZWT212904/Z/18/ZAS-JF-17-011WT203148/Z/16/ZMR/V027883/1Osterdahl MFLouca PValdes AMChan ATPenamakuri SSudre CHCapdevila JAntonelli MPolidori LSteves CJMay ACanas LMenni CFigueiredo JCHu CHammers ADavid SPMolteni ESpector TDWolf JOurselin SModat MNogal AFox BfalseSymptom prevalence, duration, and risk of hospital admission in individuals infected with SARS-CoV-2 during periods of omicron and delta variant dominance: a prospective observational study from the ZOE COVID Study.<h4>Background</h4>The SARS-CoV-2 variant of concern, omicron, appears to be less severe than delta. We aim to quantify the differences in symptom prevalence, risk of hospital admission, and symptom duration among the vaccinated population.<h4>Methods</h4>In this prospective longitudinal observational study, we collected data from participants who were self-reporting test results and symptoms in the ZOE COVID app (previously known as the COVID Symptoms Study App). Eligible participants were aged 16-99 years, based in the UK, with a body-mass index between 15 and 55 kg/m², had received at least two doses of any SARS-CoV-2 vaccine, were symptomatic, and logged a positive symptomatic PCR or lateral flow result for SARS-CoV-2 during the study period. The primary outcome was the like2022-01-01T00:00:00Z2022 Apr2025-05-18T10:52:14.633Z2024-10-17T18:31:31.51ZS-EPMC89893963539785110.1016/S0140-6736(22)00327-0