key: cord-0774377-p4ef9l3p authors: Tartaglione, Marco; Gamberini, Lorenzo; Semeraro, Federico; Lupi, Cristian; Coniglio, Carlo; Gordini, Giovanni title: COVID‐19 suspicion and diagnosis: are we still chasing epidemiological criteria? date: 2020-05-21 journal: J Med Virol DOI: 10.1002/jmv.26042 sha: 52c48047345f837761007ee2c077e2b16f318ffc doc_id: 774377 cord_uid: p4ef9l3p Italy was the second nation after China to be most involved into the COVID‐19 outbreak. From the beginning, much attention has been attributed to the importance of epidemiological criteria (such as previous contact with confirmed COVID‐19 cases, recent journey across China or the northern Italian regions) in order to assess a suspected patient for SARS‐CoV‐2 infection. Despite this, by now evidences do exist about the possibly huge reservoir of asymptomatic patients and its underestimated ability to spread the infection. Thus, we do believe that when an infectious disease has a big ratio of asymptomatic cases, as for COVID‐19, it is simply not safe to rely on epidemiological criteria and we briefly discuss this issue throughout the few new evidences there are about. This article is protected by copyright. All rights reserved. Italy was the second nation after China to be most involved into the COVID-19 outbreak. From the beginning, much attention has been attributed to the importance of epidemiological criteria (such as previous contact with confirmed COVID-19 cases, recent journey across China or the northern Italian regions) in order to assess a suspected patient for SARS-CoV-2 infection. Despite this, by now evidences do exist about the possibly huge reservoir of asymptomatic patients and its underestimated ability to spread the infection. Thus, we do believe that when an infectious disease has a big ratio of asymptomatic cases, as for COVID-19, it is simply not safe to rely on epidemiological criteria and we briefly discuss this issue throughout the few new evidences there are about. Keywords: Coronavirus, SARS Coronavirus, Pandemic. The first person-to-person SARS-CoV-2 transmission in Italy was reported on Feb 21st, 2020 in Lombardia region 1 . Eight weeks later, while we are writing these words, Italy has reached 218'000 coronavirus disease (COVID-19) confirmed cases with at least 28'000 deaths, thus making Italy the fifth world nation in total cases and sadly the third world nation for COVID-19 related deaths (National Health System Institute data from https://www.epicentro.iss.it/coronavirus/). We hereby discuss a few issues we think worth consideration, aiming these points to be useful for nations or geographical regions that chronologically follow Italy in the pandemic's peak. When assessing incoming patients in the emergency department (ED) presenting either with fever, respiratory failure, cough or even mild symptoms as headache, weakness or generic "sore throat", healthcare personnel is likely to be asked for epidemiological criteria investigation in order to obtain the swab test or to choose whether to admit the patient into a "clean" or COVID-19 area. These criteria may include previous contacts with confirmed COVID-19 patients, recently staying or travelling through Lombardia Italian region or China. Despite this, two recent papers from Lai and Zehender 2,3 clearly demonstrate that, among the first 16 COVID-19 patients registered in northern Italy after February 21st, none of them reported a recent history of travel outside Italy. By their genetical virus analysis the authors state that SARS-CoV-2 was allegedly already circulating in Italy by the end of January 2020, demonstrating therefore that Italian cases of SARS-CoV-2 are strictly related with the Latin America ones and both possibly follow the Germany strain that came first in Europe during January 2020. To our experience, our Trauma Intensive Care Unit (ICU) at Maggiore Hospital in Bologna admitted by the end of February a trauma patient that was presumed healthy at the circumstance of trauma and turned out SARS-CoV-2 positive at the swab test on ICU admission. Same results for a case of presumed "clean" ROSC after out-of-hospital cardiac arrest (OHCA), found to be COVID-19 case. Moreover, after publication of the largest case series to date regarding COVID-19 in China by Wu et al 4 , then followed by the confirmation for the SARS-CoV-2 to be transmitted by asymptomatic carrier by Bai and colleagues 5 , the Italian independent foundation "GIMBE Evidence for Health" at the end of March 2020 cross-matched the first available Chinese cohort with the Italian data coming to envisioning that official statistics may be missing roughly 65% of COVID-19 cases (https://coronavirus.gimbe.org), being these asymptomatic or mild-symptoms patients (Figure 1 ). If from one side this is good new because it would flatten down the death and critically ill patients rate, from the other way around this would mean that 65% of COVID-19 patients were free to circulate before the implementation of quarantine. These findings were further confirmed by Bay 6 II. Italy has unfortunately got the record for COVID-19 cases among healthcare workers (HCWs) and, apparently, the majority of these are found among Surgical and Operatory Theatre personnel. This may mean that HCWs infections are likely to be greater within hospital paths meant to be "clean", and we can hypothesize that this happens because this personnel feel less degree of risk and is thus prone to use less personal protective equipment (PPE) or they use it in an inappropriate way. Furthermore, another HCWs category that is hugely affected is the General Practitioners' one: this time maybe because out of hospital there are less barrier between patients and staff and there are no filter zones where HCWs can dress-up in a proper way and decontaminate at the end of a patient's assessment. Thus, in order to avoid the personnel to underestimate the risks, despite the need and recognized importance of separated paths between suspected/confirmed COVID-19 and clean patients, we aim that HCWs began to manage each patient as suspected until both negative swab and imaging are obtained, since even swab tests have a negative predictive value well below certainty. Moreover, this gains relevance especially in the context of urgent patient's assessment and procedures where COVID-19 risks criteria (clinical, imaging and laboratoristical findings) cannot be easily ruled-out. Conclusion. The first italian COVID-19 cases are likely to be dated back to early February 2020. A huge percentage of infections may happen between asymptomatic people that, up to today, have no more connection with northern Italy or China cases. Suspicion or diagnosis of COVID-19 cases should not need to match epidemiological criteria. When managing a patient suspected for COVID-19 and even when assessing a healthy patient, all HCW personnel should use PPE based both on the grade of probability of SARS-CoV-2 infection, that considers clinical, laboratoristical and imaging criteria, and the risk of the procedure that has to be done. The response of Milan's Emergency Medical System to the COVID-19 outbreak in Italy. The Lancet Early phylogenetic estimate of the effective reproduction number of SARS-CoV-2 GENOMIC CHARACTERISATION AND PHYLOGENETIC ANALYSIS OF SARS-COV-2 IN ITALY. CSH, BMJ Characteristics of and Important Lessons From the Coronavirus Disease 2019 (COVID-19) Outbreak in China. Summary of a Report of 72 314 Cases From the Chinese Center for Disease Control and Prevention Presumed Asymptomatic Carrier Transmission of COVID-19 Covid-19: four fifths of cases are asymptomatic, China figures indicate This article is protected by copyright. All rights reserved Figure Figure 1 : Difference between confirmed and estimated COVID-19 cases upon March 26th in Italy, based on Chinese cohort projection. Critical patients estimation goes from 5% to 2% while case fatality rate from 10,1% to 3.9%. Infographic with permission by the independent health data foundation "GIMBE Evidence for Health".