Retrospective screening for SARS‐CoV‐2 among influenza‐like illness hospitalizations: 2018–2019 and 2019–2020 seasons, Valencia region, Spain

Abstract On 9 March 2020, the World Health Organization (WHO) Global Influenza Programme (GIP) asked participant sites on the Global Influenza Hospital Surveillance Network (GIHSN) to contribute to data collection concerning severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2). We re‐analysed 5833 viral RNA archived samples collected prospectively from hospital admissions for influenza‐like illness (ILI) in the Valencia Region of Spain by the Valencia Hospital Surveillance Network for the Study of Influenza and Other Respiratory Viruses (VAHNSI) network (four hospitals, catchment area population 1 118 732) during the pre‐pandemic 2018/2019 (n = 4010) and pandemic 2019/2020 (n = 1823) influenza seasons for the presence of SARS‐CoV‐2. We did not find evidence for community‐acquired SARS‐CoV‐2 infection in hospital admissions for ILI in our region before early March 2020.


| INTRODUCTION
The first case of coronavirus disease 2019 (COVID- 19) due to severe acute respiratory syndrome coronavirus (SARS-CoV-2) was detected in Wuhan (Hubei province, China) at the end of 2019, and the virus rapidly spread to other Chinese provinces and countries. 1 As of 3 June 2020, the World Health Organization (WHO) had already reported the presence of SARS-CoV-2 in 54 different European countries. 2 In Spain, the first imported and locally acquired COVID-19 cases were detected on 31 January and 26 February 2020, respectively. 3,4 Since then, until beginning of June, Spain accounted for 240 660 confirmed cases and 27 133 deaths. Among total registered deaths, 86% were in people aged 70 or older, and 95% had previous underlying chronic conditions. 5 Symptomatology described by SARS-CoV-2-infected patients was almost identical to the common influenza-like illness (ILI) symptoms, 6,7 and COVID-19 cases may have occurred in Spain earlier than previously recognized. 8 Prevention and Control (ECDC) ILI case definition, 9 defined as the   presence of, at least, one systemic symptom (fever or feverishness, malaise, myalgia or headache) and, at least, one respiratory symptom (shortness of breath, sore throat or cough), with an onset of symptoms in the 7 days prior to admission. For children less than 5 years old, we only require an onset of one symptom (Table S1) in the 7 days prior to admission. Finally, patients need to be in hospital between 8 and 48 h to be enrolled and swabbed (combined nasopharyngeal and oropharyngeal in universal transport medium), after written informed consent. Clinical and demographic characteristics from patients were obtained by a face-to-face interview or by consulting medical records.

| DISCUSSION
To our knowledge, our study is the first comprehensive screening for SARS-CoV-2 in ILI cases at the population level in the pre-pandemic period in Europe. We describe here the first SARS-CoV-2 admission in the Valencia Region without travel history and thus likely due to community transmission in early March 2020. The infected patient was an old diabetic man in his late 70s who was also developing a neoplasia.
It is widely known that COVID-19 mainly affects elderly people 12,13 as well as people with underlying chronic conditions 14  The first SARS-CoV-2 cases in hospital admissions in Europe had been identified at the end of January or early February 2020 as related to travel to, or to contacts with, travellers from China. [26][27][28] Later, retrospective analysis identified earlier cases from early or late

CONFLICT OF INTEREST
The authors declare the following financial interests/personal relationships that may be considered as potential competing interests: FXL, F I G U R E 2 Number of detections for 19 respiratory viruses in the VAHNSI network during the 2019/2020 influenza season by epidemiological week (1 November 2019 to 14 March 2020). The timing for the first ILI admission positive for SARS-CoV-2 is indicated BMC, AMI and JDD report funding from Sanofi Pasteur, other than corresponding to the study. Data collection was partially supported by a grant from the Foundation for Influenza Epidemiology (FIE), which supports the Global Influenza Hospital Surveillance Network (see www.gihsn.org for more details). The sponsor did not participate in the study design, data analysis and interpretation, in the writing of the manuscript or in the decision to submit the manuscript for publishing.

PEER REVIEW
The peer review history for this article is available at https://publons. com/publon/10.1111/irv.12899.

DATA AVAILABILITY STATEMENT
De-identified data that support the findings of this study are available on request from the corresponding author. The data are not publicly available due to privacy or ethical restrictions.