corona virus-Covid19

COVID-19: Individual Symptoms and Severity Found to Be Be Not Useful For Self-Isolation Guidance in the Absence of Testing Interview with:

Dr Emma Wall Senior Clinical Research Fellow, UCLH-Crick Legacy study Consultant Infectious Diseases UCLH

Dr. Wall

Dr Emma Wall
Senior Clinical Research Fellow, UCLH-Crick Legacy study
Consultant Infectious Diseases UCLH  What is the background for this study? 

Response: Since April 2022, both the UK and US have changed their COVID-19 isolation and testing policies. The impact these changes in the guidance and vaccination on community-acquired COVID-19 caused by recent SARS-CoV-2 variants of concern (VOC) has not been fully tested, including infections with BA.2. We aimed to characterise both symptoms and viral loads over the course of COVID-19 infection in otherwise-healthy, vaccinated, non-hospitalised adults, to assess whether current guidance remains justified. All participants were included in the UCLH-Crick Legacy study, a prospective, observational cohort study of otherwise healthy adults who have been taking part in regular workplace testing for SARS-CoV-2 in London

We sent swabs by same-day courier every other day to all adults who reported a positive PCR or lateral flow test to the study team up to day 10 after the start of each infection. We confirmed which variant caused the infection by PCR and sequencing. All participants completed linked symptom diaries.

We compared symptoms and changes in the amount of virus detected in the nose and throat during infection between study participants reporting COVID-19 caused by VOCs Delta and Omicron BA.1 and BA.2. We then analysed how many of our participants would meet current UK/US isolation guidelines.  What are the main findings?

Response: We found non-hospitalised, vaccinated adults infected with Omicron BA.1 and BA.2 most frequently reported symptoms of coryza (stuffy nose/cold-like symptoms), cough and fatigue. Compared to Delta infections, the earlier ‘classical triad’ of COVID-19 symptoms: fever, anosmia and shortness of breath were rare with Omicron, despite similar levels of virus in the nose and throat, self-reported infection severity and symptom duration across all infections. We found the highest levels of virus were found 3-5 days following symptom onset. What should readers take away from your report?

Response: Our study suggests that less than 50% of adults with COVID-19 caused by Omicron BA. and BA.2 would current meet NHS/CDC isolation advice. Individual symptoms and their severity are not useful guidance for self-isolation in the absence of testing.

Healthcare policy makers need to keep vaccination strategies, national and workplace testing and isolation guidelines under review for each new variant that emerges. 

No relevant COI/Disclosures 


Non-hospitalised, vaccinated adults with COVID-19 caused by Omicron BA.1 and BA.2 present with changing symptom profiles compared to those with Delta despite similar viral kinetics

Hermaleigh Townsley, Edward J Carr, Timothy W Russell, Lorin Adams, Harriet V Mears, Chris Bailey, James RM Black, Ashley S Fowler, Katalin Wilkinson, Matthew Hutchinson, Ruth Harvey, Bobbi Clayton, Gavin Kelly, Rupert Beale, Padmasayee Papineni, Tumena Corrah, Simon Caidan, Jerome Nicod, Steve Gamblin, George Kassiotis, Vincenzo Libri, Bryan Williams, Sonia Gandhi, Adam J Kucharski, Charles Swanton, Emma C Wall, David LV Bauer

medRxiv 2022.07.07.22277367; doi:

This article is a preprint and has not been peer-reviewed [what does this mean?]. It reports new medical research that has yet to be evaluated and so should not be used to guide clinical practice.

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Last Updated on August 2, 2022 by Marie Benz MD FAAD