COVID-19 Risk Assessment

Enter symptoms, answer questions, and receive a score indicating the COVID-19 risk as high, medium or low. We take also +20,000 other possible causes into consideration. Our solution performs at 96.32% accuracy for symptomatic cases (see scientific study results below) and is CE marked as a medical device.

Medical Device Class I per Council Directive 93/42/EEC
29 of 30 COVID-19 cases detected in symptomatic patients
1,071 of 1,112 symptomatic cases correctly classified as "low risk" for COVID-19 in patients with symptoms
In 1,100 of 1,142 symptomatic cases prediction was correct

The indicated sensitivity, specificity and accuracy was evaluated based on symptomatic cases. These values may not be transferred for the purposes of identifying a current COVID-19 infection, especially for a presymptomatic or asymptomatic disease presentation. The COVID-19 chatbot does not represent an in-vitro-diagnostic device (e.g. PCR-Tests).

Martin, A., Nateqi, J. et al. Nature publication doi:
COVID-19 chatbot

Enter symptoms, answer questions, and receive a score indicating the COVID-19 risk.

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Validation of Symptoma’s Chatbot for COVID-19
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Study validating our accuracy in scoring COVID-19 risk

An artificial intelligence based first-line defence against COVID-19: digitally screening citizens for risks via a chatbot

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COVID-19 abstract

Sensitivity and Specificity

Symptoma correctly classifies 29 of 30 symptomatic COVID-19 cases as COVID-19 risk (96.6% sensitivity). Of 1,112 British Medical Journal (BMJ) control cases (non-COVID-19), only 41 are classified as potential COVID-19 cases by Symptoma, with only seven of these ranking COVID-19 higher than the correct diagnoses. These seven cases relate to diseases that present similarly to COVID-19, however, have far lower incidence rates and, therefore, are deemed less likely, e.g. Severe Acute Respiratory Syndrome (SARS-CoV) or the Avian influenza A (H5N1) virus infection (bird flu). The results are summarized in the table below.

 n casesFlagged as COVID-19 riskNot flagged as COVID-19 risk
COVID-19 cases3029 True Positives1 False Negatives
BMJ cases1,11241 False Positives1,071 True Negatives
Symptoma performance
Symptoma performs better than other approaches

Differentiation of symptomatic COVID-19 cases vs non-COVID-19 cases by Symptoma, four other questionnaire-based approaches and a Symptoma variant (n = 394).

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Discovery Speed and Sensitivity

Identification of symptomatic COVID-19 cases with regards to the number of query terms entered. On the x-axis, the search rank of the query in Symptoma is given against the y-axis where each panel considers a different number of symptoms in the query. Only reported COVID-19 symptoms are considered. Points are jittered vertically for clarity only.

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COVID-19 search rank
Symptoma differentiation

Although symptoms are very similar, Symptoma seems to correctly differentiate COVID-19 from other diseases, e.g. the common cold, hay fever and the flue (see Fig 2b).

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Further study confirms Symptoma’s leading accuracy for COVID-19 among +10 other solutions worldwide.

A benchmark of online COVID-19 symptom checkers

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COVID-19 abstract


Clinical Cases

A total of 50 COVID-19 cases were extracted by three trained medical doctors from the literature and are listed in S3 Table. Each case describes one patient’s medical situation, i.e. symptoms experienced and COVID-19 contacts. Extreme edge cases of COVID-19 such as patients with several severe comorbidities were not included in this study.

COVID-19 Cases

We used a total of 460 clinical cases to evaluate the performance of the COVID-19 symptom checkers. Each case lists both, symptoms and the correct diagnosis, alongside the age and sex of the patient when available. Details of the two case sets used are given below and in Table 2.

Control Cases

COVID-19 cases allow us to evaluate the sensitivity of symptom checkers. To also evaluate the specificity, 410 control cases from the British Medical Journal (BMJ) were sourced [6,7]. To allow a fair assessment, we only used cases containing at least one of the COVID-19 symptoms (see S4 Table) reported by the WHO [5].

Classifying non-relevant cases (e.g. a fracture) would overestimate the symptom checkers’ specificity. Furthermore, these patients would not consult an online COVID-19 symptom checker. None of these 410 BMJ cases has COVID-19 listed as the diagnosis as the cases where collected before the COVID-19 outbreak.

Symptoma differentiation
Accuracy Rates

Symptoma shows the overall highest accuracy rate for COVID-19. Even SF-COS and SF-DIST (two alternative algorithms developed by Symptoma within a few hours each) perform higher than almost all other solutions.

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