key: cord-0029664-67uxqub1
authors: Houhamdi, Linda; Fournier, Pierre-Edouard
title: Smart apps for self-reporting clinical information
date: 2022-04-07
journal: Lancet
DOI: 10.1016/s0140-6736(22)00453-6
sha: 43d7fc3ade6137d8d811e7c60dd8d0635d32f64e
doc_id: 29664
cord_uid: 67uxqub1

nan

The global COVID-19 pandemic has placed unprecedented health, economic, and social pressures on nations worldwide. Following the initial Wuhan-Hu-1 variant, various genetic lineages of SARS-CoV-2 have emerged and circulated around the world, most notably the five successive variants of concern, alpha (B.1.1.7), beta (B.1.351), gamma (P.1), delta (B.1.617.2), and omicron (B.1.1.529). 1, 2 Understanding both the characteristics of COVID-19 and the dynamics of its causative variants constitutes a crucial milestone in preventing transmission and reducing infection, hospital admission, and death. Large-scale tracking tools that use simple and accessible devices and enable rapid and widespread analyses are extremely desirable.

In May, 2020, Cristina Menni and colleagues 3 reported the use of a free smartphone app to capture various self-reported symptoms, hospital admissions, results of RT-PCR or lateral flow antigen tests, demographic information, and pre-existing medical conditions, to identify the most predictive symptoms of COVID-19. This application, named ZOE, provided insight into the usefulness of COVID-19 symptom tracking. 3 Indeed, the combination of just four symptoms (anosmia, fatigue, persistent cough, and loss of appetite) allowed the identification of individuals infected in previous waves. 3 In The Lancet, 4 the same team reports their use of the ZOE app to quantify the prevalence and duration of each of 32 COVID-19-related symptoms and the risk of hospital admission in individuals who had received two or three doses of any SARS-CoV-2 vaccine and who were infected during periods of either omicron or delta variant prevalence in the UK. Patients were matched 1:1 for age, gender, and vaccination dose. By comparison with other studies, [5] [6] [7] Menni and colleagues report that omicron infections were associated with less anosmia and involvement of the lower respiratory tract, and a shorter duration of the acute phase, whereas deltainfected patients had less hoarseness and sore throat. 4 Moreover, patients who received a booster vaccine had a greater reduction in symptoms and were twice as likely to recover within one week of the onset of omicron symptoms than were those who had received two doses, or those infected with delta who had received either two or three doses. 4 This study has multiple strengths. First, it is a prospective survey with a 1:1 matching design, and uses an emerging concept, ie, real-time recording of multiple clinical symptoms based on self-reported information from the participants themselves. Second, the cohort of fully or booster-vaccinated individuals subsequently infected with either omicron or delta variants was large. And last, but not least, it was the first study to detail every symptom and duration of acute illness in every infected vaccine recipient.

Mobile apps to monitor diseases are highly valuable 8 and can easily be implemented worldwide and in various languages. However, this strategy has several limitations, as acknowledged by Menni and colleagues. 4 First, the relevance of each item did not seem to be explained to participants in order to increase their involvement and attendance, and the use of error reminders at each stage of completing the online form is important. Second, participants younger than 16 years and those with body-mass index greater than 55 kg/m 2 were excluded. 4 However, patients in these categories should not be overlooked when working with COVID-19. Indeed, omicron cases have been reported in patients younger than 16 years, 6 and obesity is an indisputable comorbidity factor in the severity of COVID-19. Third, patients who reported symptoms within 7 days after vaccination were excluded because symptoms in this period might reflect reactions to the vaccine and not be due to This assumption can underestimate early post-vaccine infections.

Finally, addition of information not currently explored should be possible, such as history of a previous episode of COVID-19; possible co-infection with another respiratory pathogen; variant confirmation by screening genotyping or genomic sequencing; creation of a unique and lifetime identifier per individual; and specialised consultations for better management of participants.

As of Feb 21, 2022, COVID-19 has caused 424 718 523 confirmed cases and 5 889 150 deaths worldwide. 9 The severity of this disease and the unprecedented ability of SARS-CoV-2 to modify its genome and spread in successive waves highlights the usefulness of easyto-use mobile apps such as ZOE to rapidly assess the characteristics of a new variant and implement optimised management measures. www 

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SARS-CoV-2 variant classifications and definitions

Real-time tracking of self-reported symptoms to predict potential COVID-19

A comparison of SARS-CoV-2 symptom prevalence, duration, and risk of hospitalisation among vaccinated individuals from the ZOE COVID Study during omicron versus delta variant dominant periods

Epidemiological characterisation of the first 785 SARS-CoV-2 omicron variant cases in Denmark

Characteristics of the first 1119 SARS-CoV-2 Omicron variant cases

Early assessment of the clinical severity of the SARS-CoV-2 omicron variant in South Africa: a data linkage study

Feasibility of using a mobile app to monitor and report COVID-19 related symptoms and people's movements in Uganda

COVID-19: daily dashboard