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Currently submitted to: JMIR Public Health and Surveillance

Date Submitted: Jun 27, 2020
Open Peer Review Period: Jun 27, 2020 - Jul 11, 2020
(currently open for review)

Warning: This is an author submission that is not peer-reviewed or edited. Preprints - unless they show as "accepted" - should not be relied on to guide clinical practice or health-related behavior and should not be reported in news media as established information.

Self-reported symptoms of SARS-CoV-2 infection in a non-hospitalized population: data from the large Italian web-based EPICOVID19 cross-sectional survey

  • Fulvio Adorni; 
  • Federica Prinelli; 
  • Fabrizio Bianchi; 
  • Andrea Giacomelli; 
  • Gabriele Pagani; 
  • Dario Bernacchia; 
  • Stefano Rusconi; 
  • Stefania Maggi; 
  • Caterina Trevisan; 
  • Marianna Noale; 
  • Sabrina Molinaro; 
  • Luca Bastiani; 
  • Loredana Fortunato; 
  • Nithiya Jesuthasan; 
  • Aleksandra Sojic; 
  • Carla Pettenati; 
  • Marcello Tavio; 
  • Massimo Andreoni; 
  • Claudio Mastroianni; 
  • Raffaele Antonelli Incalzi; 
  • Massimo Galli; 



Understanding the occurrence of Severe Acute Respiratory Syndrome-Coronavirus-2 (SARS-CoV-2)-like symptoms in a large non-hospitalized population, when the epidemic peak was occurring in Italy, is of paramount importance but data are scarce.


Aims of this study were to evaluate the association of self-reported symptoms with SARS-CoV-2 nasopharyngeal swab (NPS) test in non-hospitalized individuals and to estimate the occurrence of COVID-19-like symptoms in a larger non-tested population.


This is an Italian countrywide self-administered cross-sectional web-based survey on voluntary adults who completed an anonymous questionnaire in the period 13-21 April 2020. The associations between symptoms potentially related to SARS-CoV-2 infection and NPS results were calculated as adjusted odds ratios with 95% confidence intervals (aOR, 95%CI) by means of multiple logistic regression analysis controlling for age, sex, education, smoking habits, and the number of co-morbidities. Thereafter, for each symptom and for their combination, we calculated sensitivity, specificity, accuracy and AUC in a ROC analysis to estimate the occurrence of COVID-19-like infections in the non-tested population.


A total of 171,310 responded to the survey (59.9% females, mean age 47.4 years). Out of the 4,785 respondents with known NPS test result, 4,392 were not hospitalized. Among them, the NPS positive respondents (n=856) most frequently reported myalgia (61.6%), olfactory and/or taste disorders (OTDs, 59.2%), cough (54.4%), and fever (51.9%) whereas 7.7% were asymptomatic. Multiple regression analysis showed that OTDs (aOR 10.3, [95%CI 8.4-12.7]), fever (2.5, 95%CI 2.0-3.1), myalgia (1.5, 95%CI 1.2-1.8), and cough (1.3, 95%CI 1.0-1.6) were associated with NPS positivity. Having two to four of these symptoms increased the aOR from 7.4 (95%CI, 5.6-9.7) to 35.5 (95%CI, 24.6-52.2). The combination of the four symptoms showed an AUC of 0.810 (95%CI 0.795-0.825) in classifying NPS-P, and was applied to the non-hospitalized and non-tested sample (n=165,782). We found that from 4.4% to 12.1% of respondents had experienced symptoms suggestive of COVID-19 infection.


Our results suggest that self-reported symptoms may be reliable indicators of SARS-CoV-2 infection in a pandemic context. A not negligible part (up to 12.1%) of the symptomatic respondents were left undiagnosed and potentially contributed to the spread of the infection.


Please cite as:

Adorni F, Prinelli F, Bianchi F, Giacomelli A, Pagani G, Bernacchia D, Rusconi S, Maggi S, Trevisan C, Noale M, Molinaro S, Bastiani L, Fortunato L, Jesuthasan N, Sojic A, Pettenati C, Tavio M, Andreoni M, Mastroianni C, Antonelli Incalzi R, Galli M

Self-reported symptoms of SARS-CoV-2 infection in a non-hospitalized population: data from the large Italian web-based EPICOVID19 cross-sectional survey

JMIR Preprints. 27/06/2020:21866

DOI: 10.2196/preprints.21866


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