When the COVID-19 Pandemic Surges during Influenza Season: Lessons Learnt from the Sentinel Laboratory-Based Surveillance of Influenza-Like Illness in Lombardy during the 2019–2020 Season

Abstract

This paper outlines the role of Lombardy’s regional influenza reference laboratory (Northern Italy) in the surveillance of influenza-like illnesses (ILIs) in monitoring SARS-CoV-2 circulation by analyzing 631 consecutive nasopharyngeal swabs (NPSs) collected from ILI outpatients by sentinel physicians during the 2019–2020 season. The samples were tested by specific real-time RT-PCRs targeting SARS-CoV-2, influenza viruses, and RSVs. Results: Of these NPSs, 31% tested positive for influenza viruses, 10% for SARS-CoV-2, and 7% for RSV. No coinfections were detected. Influenza viruses and RSVs circulated throughout the surveillance period until the end of February (week 9-2020), when they suddenly ceased to circulate seven weeks earlier than during the previous five influenza seasons. After the first detection of SARS-CoV-2 in our ILI outpatients at the beginning of March (week 10-2020), SARS-CoV-2 remained the only virus identified throughout the surveillance period. Patients ≥ 65 years had a 3.2-fold greater risk of being infected with SARS-CoV-2, while school-age children (5–14 years) and children < 5 years proved to be the age groups most at risk of contracting influenza viruses and RSV, respectively. Our experience demonstrates that laboratory-based ILI surveillance networks are essential for identifying SARS-CoV-2 cases that would otherwise remain undetected, in order to stop their spread within our communities.

The impact of COVID‐19 on new mesothelioma diagnoses in Italy

“…The increase in the pre-pandemic period could be linked to early diagnosis of MM in people presenting respiratory symptoms in a silent phase of the pandemic. Nevertheless, detailed epidemiological and virology 9 investigations conducted on data from the beginning of the early phases of the pandemic in Italy showed that only a few hundred COVID-19 patients sought care before 20 February 2020, 10 and the seasonal influenza virus was predominant until the end of February 2020. 9 However, the data show some geographical differences.…”

“…Nevertheless, detailed epidemiological and virology 9 investigations conducted on data from the beginning of the early phases of the pandemic in Italy showed that only a few hundred COVID-19 patients sought care before 20 February 2020, 10 and the seasonal influenza virus was predominant until the end of February 2020. 9 However, the data show some geographical differences. The patterns of increase and decrease in the number of diagnoses during the different phases of the pandemic do not show any association with regional COVID-19 incidence nor with the physical distancing measures.…”

Waiting for the truth: is reluctance in accepting an early origin hypothesis for SARS-CoV-2 delaying our understanding of viral emergence?

“…Some studies that retrospectively screened respiratory samples collected from patients with influenza-like and respiratory symptoms, including those collected within the framework of influenza surveillance, found no evidence for SARS-CoV-2 (table 2),37–41 including during times when community SARS-CoV-2 transmission in respective populations was already occurring 20. Nonetheless, the combination of all knowledge acquired so far from retrospective studies strongly suggests that SARS-CoV-2 was circulating outside of China considerably earlier than the currently postulated time frame of late December 2019/early January 2020, at least in some parts of the world.…”

The associations of previous influenza/upper respiratory infection with COVID-19 susceptibility/morbidity/mortality: a nationwide cohort study in South Korea

“…However, a serum antibody test study demonstrated that although approximately 23% of COVID-19 patients had SARS-CoV-2 cross-reactive antibodies during the prepandemic period, these antibodies were not neutralizing antibodies for SARS-CoV-2 and were not related to reducing COVID-19 susceptibility and hospitalization 20 . A cross-sectional study reported different contracting patterns of influenza viruses and SARS-CoV-2 21 . There were no coinfected cases in their study, and SARS-CoV-2 infection was higher in elderly individuals, while influenza virus infection was more prevalent in children less than 5 years old 21 .…”

“…A cross-sectional study reported different contracting patterns of influenza viruses and SARS-CoV-2 21 . There were no coinfected cases in their study, and SARS-CoV-2 infection was higher in elderly individuals, while influenza virus infection was more prevalent in children less than 5 years old 21 . Furthermore, the antiinfection effects of nonpharmacologic interventions, such as wearing face masks, social distancing, restrictions on movement and health behaviors of infected patients, could mediate the decreased COVID-19 incidence in patients with influenza/URI 22 – 24 .…”