Circulation of SARS-CoV-2 Variants among Children from November 2020 to January 2022 in Trieste (Italy)

Introduction: The ongoing coronavirus disease 19 (COVID-19) outbreak involves the pediatric population, but to date, few reports have investigated the circulation of variants among children. Material and Methods: In this retrospective study, non-hospitalized pediatric patients with SARS-CoV-2-positive nasopharyngeal swabs (NPS) were enrolled at the Institute for Maternal and Child Health-IRCCS Burlo Garofolo, Trieste (Italy), from November 2020 to January 2022. SARS-CoV-2 variants were identified by in vitro viral isolation, amplification, automatic sequencing of the receptor binding domain (RBD) of the SARS-CoV-2 spike coding gene, and subsequent next-generation sequencing. The growth curves of the isolated strains were defined in vitro by infecting Vero-E6 cells and quantifying the viral load in the supernatants up to 72 h post-infection by qRT–PCR. The neutralization activity of sera obtained from a COVID-19 vaccinated subject, recovered (2020) patient, vaccinated and recovered (2021) patient, and seronegative subject was assessed by microneutralization assay against the different variants. Results: In total, 32 SARS-CoV-2-positive children, 16 (50%) females, with a median age of 1.4 years (range: 1 day–13 years), were enrolled. The D614G amino acid substitution was detected in all isolated and amplified viral strains. Of the 32 isolates, 4 (12.5%) carried a nonsynonymous nucleotide mutation leading to the N439K (3/4), lineage B.1.258 (∆H69/∆V70), and S477N (1/4) substitution. In 7/32 (21.8%) isolates, amino acid substitutions allowed the identification of a delta variant, lineage B.1.617.2-AY.43, and in 1/32 (3.1%), the Omicron strain (B.1.1.529.BA1) was identified. The growth curves of the B.1, B.1.258 (∆H69/∆V70), B.1.617.2-AY.43, and B.1.1.529.BA1 variants did not show any significant differences. A reduction in the serum neutralizing activity against B.1.258 (∆H69/∆V70) only in a vaccinated subject (1.7-fold difference), against B.1.617.2-AY.43 in a vaccinated subject and in recovered patients (12.7 and ≥2.5-fold differences, respectively), and against B.1.1.529.BA1 variant (57.6- and 1.4-fold differences in vaccinated and in vaccinated and recovered patients) were observed compared to the B.1 variant. Conclusions: SARS-CoV-2 variants carrying the B.1.258 (∆H69/∆V70) and S477N substitutions were reported here in a pediatric population for the first time. Although the growth rates of the isolated strains (B.1.258, B.1.617.2-AY.43, B.1.1.529.BA1) did not differ from the B.1 variant, neutralizing activity of the sera from vaccinated subjects significantly decreased against these variants. Attention should be devoted to the pediatric population to prevent the spread of new SARS-CoV-2 variants in an unvaccinated and predominantly naive population.

COVID-19 Test Before Tokyo2020 Paralympic Games: An Implemented Protocol to Protect Paralympic Athletes

Objectives

The COVID-19 pandemic represents a difficult challenge for the whole of humanity. Sports, in which contact between athletes is essential, became impossible to practice without the risk of viral spread. Athletes of the national teams are a particular subgroup of the population for whom there is an important need for protection and the implementation of targeted preventive measures. The present report describes the protocol that was developed to answer the urgent protection need for athletes during COVID-19 pandemic. The protocol aimed at demonstrating the feasibility of a rigid prevention intervention to prevent outbreaks and infections in terms of COVID-19 as well as in other potential future pandemics from pathogens with similar path of transmission.

Methods

The study was conducted in rowing para-thletes training of the Paralympic Games in Tokyo2020. It was designed to create an anti-COVID-19 “protection bubble” with the aim to isolate para-athletes and their technical support team during pre-Olympic retreats. The “bubble” development relied on a carefully conducted protocol of repeated antigen and molecular COVID-19 tests on nasal and oropharyngeal fluids among all participants carried out before, during and at the end of each retreat.

Results

During the 10 months of protocol implementation there were no COVID-19 outbreaks among the para-athletes and technical personnel during the retreats. In total, 552 PCR tests and 298 antigen-based tests were performed for an average number of 42 test per athlete. The number of retreat participants was larger (n = 23) in the beginning of the year due to the Paralympic selection rounds and smaller at the end of the study period (n = 12).

Conclusion

The protocol has indicated that it is possible to implement an anti-COVID-19 protection protocol where athletes and technical staff can train and compete in safe conditions. The study showed that it is feasible to implement a rigid prevention protocol for athletes and technical staff based on repeated COVID-19 antigenic and molecular tests for a long period of training with excellent participation and compliance.

SARS-CoV-2 RNA in urban wastewater samples to monitor the COVID-19 pandemic in Lombardy, Italy (March-June 2020)

Wastewater-based viral surveillance was proposed as a promising approach to monitor the circulation of SARS-CoV-2 in the general population. The aim of this study was to develop an analytical method to detect SARS-CoV-2 RNA in urban wastewater, and apply it to follow the trends of epidemic in the framework of a surveillance network in the Lombardy region (Northern Italy). This area was the first hotspot of COVID-19 in Europe and was severely affected. Composite 24 h samples were collected weekly in eight cities from end-March to mid-June 2020 (first peak of the pandemic). The method developed and optimized, involved virus concentration using PEG centrifugation, and one-step real-time RT-PCR for analysis. SARS-CoV-2 RNA was identified in 65 (61%) out of 107 samples, and the viral concentrations (up to 2.1 E + 05 copies/L) were highest in March-April. By mid-June, wastewater samples tested negative in all the cities corresponding to the very low number of cases recorded in the same period. Viral loads were calculated considering the wastewater daily flow rate and the population served by each wastewater treatment plant, and were used for inter- city comparison. The highest viral loads were found in Brembate, Ranica and Lodi corresponding to the hotspots of the first peak of pandemic. The pattern of decrease of SARS-CoV-2 in wastewater was closely comparable to the decline of active COVID-19 cases in the population, reflecting the effect of lock-down. This study tested wastewater surveillance of SARS-CoV-2 to follow the pandemic trends in one of most affected areas worldwide, demonstrating that it can integrate ongoing virological surveillance of COVID-19, providing information from both symptomatic and asymptomatic individuals, and monitoring the effect of health interventions.

Longitudinal, virological, and serological assessment of hospitalized COVID-19 patients

Here we described the virological and serological assessment of 23 COVID-19 patients hospitalized and followed up in Milan, Italy, during the first wave of COVID-19 pandemic. Nasopharyngeal (NPS), anal swabs, and blood samples were collected from 23 COVID-19 patients, at hospital admission, and periodically up to discharge, for a median time of 20 days (3-83 days). RNA was isolated and tested for SARS-CoV-2 by qRT-PCR; anti-SARS-CoV-2 IgM and IgG antibody titers were evaluated in serum samples by ELISA. SARS-CoV-2 genome was detected in the NPS swabs of the 23 patients, at the admission, and 8/19 (42.1%) were still positive at the discharge. Anal swabs were positive to SARS-CoV-2 RNA detection in 20/23 (86.9%) patients; 6/19 (31.6%) were still positive at discharge. The mean time of RNA negative conversion was 17 days (4-36 days) and 33 days (4-77 days), for NPS and anal swabs, respectively. SARS-CoV-2-RNA was detected in the blood of 6/23 (26.1%) patients. Thirteen/23 (56.5%) and 17/23 (73.9%) patients were seropositive for IgM and IgG, respectively, at the admission, and the median IgM and IgG levels significantly (p < 0.05) increased after 13 days. Although the limited cohort size, our report provides evidence that SARS-CoV-2 is shed through multiple routes, with important implications in healthcare settings.

Characterizing the transmission patterns of seasonal influenza in Italy: lessons from the last decade

BACKGROUND

Despite thousands of influenza cases annually recorded by surveillance systems around the globe, estimating the transmission patterns of seasonal influenza is challenging.

METHODS

We develop an age-structured mathematical model to influenza transmission to analyze ten consecutive seasons (from 2010 to 2011 to 2019-2020) of influenza epidemiological and virological data reported to the Italian surveillance system.

RESULTS

We estimate that 18.4-29.3% of influenza infections are detected by the surveillance system. Influenza infection attack rate varied between 12.7 and 30.5% and is generally larger for seasons characterized by the circulation of A/H3N2 and/or B types/subtypes. Individuals aged 14 years or less are the most affected age-segment of the population, with A viruses especially affecting children aged 0-4 years. For all influenza types/subtypes, the mean effective reproduction number is estimated to be generally in the range 1.09-1.33 (9 out of 10 seasons) and never exceeding 1.41. The age-specific susceptibility to infection appears to be a type/subtype-specific feature.

CONCLUSIONS

The results presented in this study provide insights on type/subtype-specific transmission patterns of seasonal influenza that could be instrumental to fine-tune immunization strategies and non-pharmaceutical interventions aimed at limiting seasonal influenza spread and burden.

Respiratory syncytial virus in pediatric influenza-like illness cases in Lombardy, Northern Italy, during seven consecutive winter seasons (from 2014-2015 to 2020-2021)

Introduction

Respiratory syncytial virus (RSV) is the major cause of lower respiratory tract illness in young children and can also cause influenza‐like illness (ILI). Here we investigated the epidemiological features of RSV infection in pediatric ILI cases in Lombardy (a region in Northern Italy accounting nearly 10 million inhabitants) from 2014–2015 to 2020–2021 winter seasons.

Material and Methods

Data for this study were retrieved and statistically analyzed from the database of virological influenza surveillance of the regional reference laboratory for Lombardy within the Italian influenza surveillance network (InfluNet).

Results

RSV accounted for nearly 19% of pediatric ILI with a risk of infection nearly two‐fold greater than that of individuals ≥15 years. RSV positivity rate increased to 28% considering 0–5 years old children. Although in children ≤5 years the risk of infection from influenza viruses resulted nearly two‐fold higher than the risk of RSV infection, the age group 4–6 months and 7–12 months showed a five‐fold greater risk of infection from RSV than from influenza. Children ≤5 years of age with pre‐existing underlying health conditions had a nearly five‐fold greater risk of getting RSV infection than otherwise healthy 0–5 years old children. RSV was identified in ILI cases <15 years of age in all considered winter seasons except in the 2020–2021 season.

Discussion

Sentinel surveillance of ILI allowed us to identify groups at higher risk of RSV and influenza infection and to define the start, duration, timing, and intensity of the RSV and influenza community circulation. This surveillance approach can be implemented to assess the RSV circulation and impact in a real‐time manner.

VIRAL AGENTS AND SYSTEMIC LEVELS OF INFLAMMATORY CYTOKINES IN VULNERABLE AND STABLE ATHEROSCLEROTIC CAROTID PLAQUES

BACKGROUND

To investigate the presence of genetic material of viral agents and the serum level of inflammatory cytokines in patients submitted to carotid endarterectomy having vulnerable versus stable atherosclerotic plaques.

METHODS

Data of patients consecutively submitted to carotid endarterectomy for a significant stenosis from 07/2019 to 12/2019 were prospectively collected. The genetic material of Epstein-Barr (EBV), CitoMegalo (CMV), Herpes Simplex (HSV), Varicella-Zoster (VZV) and Influenza (IV) Viruses was searched in the patient's plaques, both in the "mid" of the plaque and in an adjacent lateral portion of no-plaque area. The serum levels of TNF-α, IL-1β, IL-6, IL10 and CCL5 were determined. The obtained results were then correlated to the histologic vulnerability of the removed carotid plaque. P values <0.05 were considered statistically significant.

RESULTS

Data of 50 patients were analyzed. A vulnerable plaque was found in 31 patients (62%). The genome of CMV, HSV, VZV and IV was not found in any of the vascular samples, while the EBV genome was found in the "mid" of two vulnerable plaques, but not in their respective control area. Eighty-two percent of patients who did not receive anti-IV vaccination (23/28) had vulnerable carotid plaque, compared with 36% of vaccinated patients (8/22, p=0.001). Serum levels of TNF-α and IL-6 were higher in patients with a vulnerable plaque compared to patients with a stable plaque (73.6±238.2 vs 3.9±13.1 pg/ml, p=0.01, and 45.9±103.6 vs 10.1±25.3 pg/ml, p=0.01, respectively), independent of comorbidities, viral exposure or flu vaccination.

CONCLUSION

The EBV genome was found in the "core" of two vulnerable carotid plaques, but not in their respective adjacent control. Influenza vaccination was associated with a lower incidence of carotid plaque vulnerability. Serum levels of TNF-α and IL-6 were higher in patients with a vulnerable plaque compared to patients with a stable plaque.

A comparison of coronavirus disease 2019 and seasonal influenza surveillance in five European countries: France, Germany, Italy, Spain and the United Kingdom

Background

In response to the coronavirus disease (COVID‐19) outbreak that unfolded across Europe in 2020, the World Health Organisation (WHO) called for repurposing existing influenza surveillance systems to monitor COVID‐19. This analysis aimed to compare descriptively the extent to which influenza surveillance systems were adapted and enhanced and how COVID‐19 surveillance could ultimately benefit or disrupt routine influenza surveillance.

Methods

We used a previously developed framework in France, Germany, Italy, Spain and the United Kingdom to describe COVID‐19 surveillance and its impact on influenza surveillance. The framework divides surveillance systems into seven subsystems and 20 comparable outcomes of interest and uses five evaluation criteria based on WHO guidance. Information on influenza and COVID‐19 surveillance systems were collected from publicly available resources shared by European and national public health agencies.

Results

Overall, non‐medically attended, virological, primary care and mortality surveillance were adapted in most countries to monitor COVID‐19, although community, outbreak and hospital surveillance were reinforced in all countries. Data granularity improved, with more detailed demographic and medical information recorded. A shift to systematic notification for cases and deaths enhanced both geographic and population representativeness, although the sampling strategy benefited from the roll out of widespread molecular testing. Data communication was greatly enhanced, contributing to improved public awareness.

Conclusions

Well‐established influenza surveillance systems are a key component of pandemic preparedness, and their upgrade allowed European countries to respond to the COVID‐19 pandemic. However, uncertainties remain on how both influenza and COVID‐19 surveillance can be jointly and durably implemented.

The early phase of the COVID-19 epidemic in Lombardy, Italy

Background

In the night of February 20, 2020, the first epidemic of the novel coronavirus disease (COVID-19) outside Asia was uncovered by the identification of its first patient in Lombardy region, Italy. In the following weeks, Lombardy experienced a sudden increase in the number of ascertained infections and strict measures were imposed to contain the epidemic spread.

Methods

We analyzed official records of cases occurred in Lombardy to characterize the epidemiology of SARS-CoV-2 during the early phase of the outbreak. A line list of laboratory-confirmed cases was set up and later retrospectively consolidated, using standardized interviews to ascertained cases and their close contacts. We provide estimates of the serial interval, of the basic reproduction number, and of the temporal variation of the net reproduction number of SARS-CoV-2.

Results

Epidemiological investigations detected over 500 cases (median age: 69, IQR: 57–78) before the first COVID-19 diagnosed patient (February 20, 2020), and suggested that SARS-CoV-2 was already circulating in at least 222 out of 1506 (14.7%) municipalities with sustained transmission across all the Lombardy provinces. We estimated the mean serial interval to be 6.6 days (95% CrI, 0.7–19). Our estimates of the basic reproduction number range from 2.6 in Pavia (95% CI, 2.1–3.2) to 3.3 in Milan (95% CI, 2.9–3.8). A decreasing trend in the net reproduction number was observed following the detection of the first case.

Conclusions

At the time of first case notification, COVID-19 was already widespread in the entire Lombardy region. This may explain the large number of critical cases experienced by this region in a very short timeframe. The slight decrease of the reproduction number observed in the early days after February 20, 2020 might be due to increased population awareness and early interventions implemented before the regional lockdown imposed on March 8, 2020.

•

Over 500 cases (median age: 69, IQR: 57–78) declaring symptom onset before the notification of the first case (20 February 2020) were retrospectively detected.

•

SARS-CoV-2 was already circulating in at least 222 out of 1506 (14.7%) municipalities of Lombardy.

•

The estimated mean serial interval was 6.6 days (95% CrI, 0.7–19).

•

The basic reproduction number in the 12 provinces of Lombardy ranged from 2.6 (95% CI, 2.1–3.2) to 3.3 (95% CI, 2.9–3.8).

•

A decreasing trend in the net reproduction number following the detection of the epidemic and the introduction of the first restrictive measures.

Re-emergence of enterovirus D68 in Europe after easing the COVID-19 lockdown, September 2021

We report a rapid increase in enterovirus D68 (EV-D68) infections, with 139 cases reported from eight European countries between 31 July and 14 October 2021. This upsurge is in line with the seasonality of EV-D68 and was presumably stimulated by the widespread reopening after COVID-19 lockdown. Most cases were identified in September, but more are to be expected in the coming months. Reinforcement of clinical awareness, diagnostic capacities and surveillance of EV-D68 is urgently needed in Europe.

Estimation of Reduction in Influenza Vaccine Effectiveness Due to Egg-Adaptation Changes-Systematic Literature Review and Expert Consensus

BACKGROUND

Influenza vaccines are the main tool to prevent morbidity and mortality of the disease; however, egg adaptations associated with the choice of the manufacturing process may reduce their effectiveness. This study aimed to estimate the impact of egg adaptations and antigenic drift on the effectiveness of trivalent (TIV) and quadrivalent (QIV) influenza vaccines.

METHODS

Nine experts in influenza virology were recruited into a Delphi-style exercise. In the first round, the experts were asked to answer questions on the impact of antigenic drift and egg adaptations on vaccine match (VM) and influenza vaccine effectiveness (IVE). In the second round, the experts were presented with the data from a systematic literature review on the same subject and aggregated experts' responses to round one questions. The experts were asked to review and confirm or amend their responses before the final summary statistics were calculated.

RESULTS

The experts estimated that, across Europe, the egg adaptations reduce, on average, VM to circulating viruses by 7-21% and reduce IVE by 4-16%. According to the experts, antigenic drift results in a similar impact on VM (8-24%) and IVE (5-20%). The highest reduction in IVE was estimated for the influenza virus A(H3N2) subtype for the under 65 age group. When asked about the frequency of the phenomena, the experts indicated that, on average, between the 2014 and 19 seasons, egg adaptation and antigenic drift were significant enough to impact IVE that occurred in two and three out of five seasons, respectively. They also agreed that this pattern is likely to reoccur in future seasons.

CONCLUSIONS

Expert estimates suggest there is a potential for 9% on average (weighted average of "All strains" over three age groups adjusted by population size) and up to a 16% increase in IVE (against A(H3N2), the <65 age group) if egg adaptations that arise when employing the traditional egg-based manufacturing process are avoided.

Are Epidemiological Estimates Able to Describe the Ability of Health Systems to Cope with COVID-19 Epidemic?

Introduction

The coronavirus disease 2019 (COVID-19) epidemic is an infectious disease which was declared a pandemic and hit countries worldwide from the beginning of the year 2020. Despite the emergency vigilance plans, health systems in all countries experienced a different ratio of lethality, amount of admissions to intensive care units and quarantine management of positive patients. The aim of this study is to investigate whether some epidemiological estimates could have been useful in understanding the capacity of the Italian Regional Health Services to manage the COVID-19 epidemic.

Methods

We have compared data between two different Italian regions in the Northern part of Italy (Lombardy and Veneto) and the national data to determine whether different health strategies might be significant in explaining dissimilar patterns of the COVID-19 epidemic in Italy. Data have been extracted from a public database and were available only in an aggregated form.

Results

The regions in question displayed two different health policies to face the COVID-19 epidemic: while Veneto’s health service was largely territorially oriented, Lombardy’s strategy was more hospital-centered.

Discussion

The key to facing epidemics like this one consists in identifying solutions outside of hospitals. This however requires there be well-trained general practitioners and enough healthcare personnel working outside hospitals.

Influenza Vaccination Campaign during the COVID-19 Pandemic: The Experience of a Research and Teaching Hospital in Milan

Background: During the COVID-19 pandemic, more than ever, optimal influenza vaccination coverage among healthcare workers (HCWs) is crucial to avoid absenteeism and disruption of health services, as well as in-hospital influenza outbreaks. The aim of this study is to analyze the 2020 influenza vaccination campaign, comparing it with the previous year’s in a research and teaching hospital in Northern Italy. Methods: adopting an approach based on combined strategies, three interventions were deployed: a promotional and educational campaign, vaccination delivery through both ad hoc and on-site ambulatories, and a gaming strategy. Personal data and professional categories were collected and analyzed using univariate logistic regression. Vaccinated HCWs were asked to fill in a questionnaire to describe their reasons for vaccination adherence. Results: the vaccination coverage rate (VCR) was 43.1%, compared to 21.5% in 2019. The highest increase was registered among administrative staff (308.3%), while physicians represent the most vaccinated category (n = 600). Moreover, residents (prevalence ratio (PR): 1.12; 95% CI 1.04–1.20), as well as intensive care (PR: 1.44; 95% CI: 1.24–1.69) and newborn workers (PR: 1.41; 95% CI: 1.20–1.65) were, respectively, the categories most frequently vaccinated for the first time. Conclusion: the significant increase in vaccination coverage rate confirms the suitability of the combined strategy of delivering the flu vaccination campaign and represents a first step towards reaching WHO recommended vaccination rates.

A comparative study between the incidence and epidemiological features of Influenza-Like Illness and laboratory-confirmed COVID-19 cases in the Italian epicenter (Lombardy)

INTRODUCTION

In Lombardy, the influenza surveillance system relies on sentinel physicians that weekly report data on the number of Influenza-Like Illness (ILI) and a part of them also collect nasopharyngeal samples for virologic analyses. This study aims at comparing the ILI incidence of 2019-2020 influenza season with the incidence of COVID-19 cases in order to better understand the current epidemic and to evaluate whether the implementation of ILI surveillance system could succeed in early detection and monitoring of COVID-19 diffusion.

METHODS

The distribution of ILI cases in the seasons 2017-2018, 2018-2019 and 2019-2020 was taken in consideration and the curve trends were compared and analyzed according to geographical areas, age groups and time differences.

RESULTS

The curve trends presented a similar pattern up to the 9th week; in fact, a reduction in the ILI incidence rate was observed in the 2017-2018 and 2018-2019 season but in the 2019-2020 an increase in the reported ILI emerged. The relation between the numbers reported by 2019-2020 ILI surveillance and those reported for COVID-19 is supported by the curve trends, the correspondence between age groups, the correspondence by geographical location, and also by the results of the nasopharyngeal swab tests performed.

DISCUSSION

The influenza surveillance system is an effective tool for early detection of COVID-19. It may provide timely and high-quality data evaluating the SARS-CoV-2 burden among population with ILI. Implementation of the system has to be prioritized in order to identify any future novel respiratory pathogen with pandemic potential.

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

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.

Detection of IgM, IgG and SARS-CoV-2 RNA among the personnel of the University of Milan, March through May 2020: the UNICORN study

OBJECTIVES

In Italy, the pandemic of COVID-19 resulted in congestion of hospitals and laboratories and probably determined an underestimation of the number of infected subjects, as the molecular diagnosis of SARS-CoV-2 infection was mainly performed on hospitalised patients. Therefore, limited data are available about the number of asymptomatic/paucisymptomatic subjects in the general population across time. To understand SARS-CoV-2 infection in the general population, we have developed a cross-sectional study (the 'UNIversity against CORoNavirus study') to investigate infection trends in asymptomatic/paucisymptomatic subjects in Milan (Italy), between March and June 2020.

PARTICIPANTS

The study population included 2023 subjects asymptomatic at the enrolment.

PRIMARY OUTCOME MEASURES

A nasal mid-turbinate swab for the detection of SARS-CoV-2 RNA and blood specimen for testing serum antibodies (immunoglobulin M (IgM) and IgG) were collected.

RESULTS

Subjects showing positivity for the SARS-CoV-2 RNA and/or for anti-SARS-CoV-2 Ig is 237 (11.7%). Only 1.2% (n=25) of the total population had a positive nasal swab for SARS-CoV-2 and the large majority (21/25) of them were observed in March. A total of 226 subjects (11%) had IgM (n=19; 0.9%), IgG (n=155; 7.7%) or both (n=52; 2.6%) against SARS-CoV-2. Subjects with a present or past SARS-CoV-2 infection did not differ from other subjects as regards the number of cohabiting family members, travels, fever and upper and lower respiratory infection episodes.

CONCLUSIONS

Results from the present study support the hypothesis that the actual spread of the virus in Lombardy was underestimated in the official records. However, as it is not known how long Ig persist, numbers should be taken cautiously.

Isolation of SARS-CoV-2 strains carrying a nucleotide mutation, leading to a stop codon in the ORF 6 protein

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was isolated from the oro/pharyngeal swabs of two Italian COVID-19 patients, physicians in a COVID-19 division hospital, with different courses of the disease. The complete genome sequences show that the two isolates belong to the B1.1 lineage, but contain a nucleotide mutation in the ORF6, leading to a stop codon and to the deletion of 6 amino acids in the C terminus. This deletion was unique, compared to the currently available sequences deposited in the GISAID and GenBank database. It did not affect the in vitro viral replication, neither the neutralizing activities of the patients' antibodies. Based on homology analysis with other Coronaviruses, the two isolated lacked the ORF6 aminoacidic portion responsible for the inhibition of the antiviral Interferon (IFN)-based host response. IFN seems to have a dual role of in SARS-CoV-2 infected patients: not only antiviral activity, but also a detrimental role in case of excessive production. A deletion in the SARS-CoV-2 ORF6 protein might have a specific, still unknown role in the viral pathogenesis.

Evaluation of influenza vaccination efficacy in reducing influenza-related complications and excess mortality in Northern Italy (2014-2017)

OBJECTIVE

The main objective of this study was to estimate the efficacy of influenza vaccination in reducing influenza-attributable hospitalization and emergency room (ER) admission for severe complications and influenza-attributable excess mortality in individuals ≥65 years of age.

METHODS

We analyzed the ≥65 years-old community (n = 952,822) afferent to the Brescia (Northern Italy) Health Protection Agency, considered an Italian population reference, to evaluate the efficacy of influenza vaccination (seasons 2014-17) in reducing deaths, ER-admissions, and hospitalizations for influenza-related complications in the elderly.

RESULTS

A protective effect of influenza vaccination emerged in reducing hospitalization and ER admission for diseases of the respiratory system and for death from all causes in people ≥65 years. The major effect of influenza vaccination was the reduction in risk of death from all causes, increasing with age and comorbidity.

CONCLUSION

Influenza vaccination has reduced the number of ER admissions and hospitalizations caused by influenza-related complications and has prevented death among high-risk groups in elderly ≥65 years, resulting in social and public health cost savings. Stronger or new vaccination strategies are needed to improve vaccination rates among the elderly.

Self-Sampling of Oropharyngeal Swabs Among Healthcare Workers for Molecular Detection of Respiratory Viruses: A Valuable Approach for Epidemiological Studies and Surveillance Programs

This study aimed at assessing the validity of self-collected (self-sampled) oropharyngeal (OP) swabs among healthcare workers compared to those collected by trained sentinel general practitioners (GP-sampled) from individuals with influenza-like illness (ILI), to be implemented in epidemiological studies and/or surveillance programs of viral pathogens involved in community respiratory infections. In our study, OP swabs were collected from adults (>18 years) with ILI during the 2018–2019 influenza season. Two groups of samples were considered: group 1−131 self-sampled OP swabs collected by healthcare workers after being trained on the sampling procedure; group 2−131 GP-sampled OP swabs collected from outpatients by sentinel GPs operating within the Italian Influenza Surveillance Network. To assess swabbing quality, following RNA extraction, each sample was tested for the presence of the human ribonuclease P gene (RNP) by in-house real-time reverse transcriptase–polymerase chain reaction (RT-PCR). Samples with a cycle threshold (Ct) <35 were considered adequate for further virological analysis. Influenza viruses (IVs), respiratory syncytial virus (RSV), and rhinovirus (RV) genomes were detected by in-house real-time RT-PCR. All samples were positive to RNP detection with Ct <35. The mean Ct value was similar in the two groups (group 1 vs. group 2: 25.93 ± 2.22 vs. 25.46 ± 2.40; p = 0.10). IVs, RSV, and RV positivity rates were 26.7 vs. 52.7% (p < 0.01), 7.6 vs. 9.9% (p = 0.52), and 21.4 vs. 19.9% (p = 0.76), respectively. Self-sampled OP swabs resulted as valid as GP-sampled OP swabs for molecular detection of respiratory viruses. Self-swabbing can thus be a worthwhile strategy for sample collection to implement molecular surveillance of respiratory pathogens and carry out epidemiological studies, easily reaching a larger population size.

Respiratory syncytial virus in influenza-like illness cases: Epidemiology and molecular analyses of four consecutive winter seasons (2014-2015/2017-2018) in Lombardy (Northern Italy)

BACKGROUND

Besides seasonal influenza viruses (IV), several other pathogens-including respiratory syncytial virus (RSV)-are involved in clinically undistinguished influenza-like illnesses (ILIs). This study aimed at investigating the contribution of RSV in ILI cases in Lombardy (Northern Italy) during four consecutive winter seasons.

MATERIALS AND METHODS

In the framework of influenza surveillance, respiratory samples from ILI outpatients were collected from 2014-2015 to 2017-2018 season. IV-negative swabs were included in the study and analyzed to detect and molecularly characterize RSV-A and RSV-B.

RESULTS

A total of 12.9% (135/1047) of samples were positive to RSV that was mostly detected among children ≤5 years (51/183, 27.8%) and those aged 6 to 15 years (30/158, 18.9%), whereas elderly >65 years accounted for 12% of RSV cases (15/125). The median start of RSV epidemic was in the end of November, with a peak in mid-February and a width of nearly 4 months, almost overlapping seasonal influenza epidemic. RSV-A and RSV-B co-circulated in all considered seasons, with RSV-B predominating on RSV-A (63.6% vs 36.4%; P < .001). Most (85.2%) RSV-A belonged to genotype ON1 and the remaining to NA1. All RSV-B clustered within the BA genotype.

CONCLUSIONS

In this study, RSV significantly contributed to ILI cases, especially among pediatric population (<15 years), although it was detected in all age groups. RSV-B predominated on RSV-A, and the most recent evolved genotypes (BA and ON1, respectively) circulated. Investigating the epidemiological and molecular characteristics of RSV in ILI cases can increase baseline epidemiological information before the introduction of RSV vaccination.

Tobacco and e-cigarette smoking habits among Italian healthcare students

BACKGROUND

Healthcare professionals might play a significant role in tobacco control. The aims of this study were to investigate tobacco cigarette and electronic cigarette (e-cigarette) consumption among university students enrolled in courses of the healthcare area, and to understand whether training in healthcare could induce to smoking cessation.

STUDY DESIGN

Cross-sectional survey using a self-administered, structured questionnaire.

METHODS

Tobacco smoking habits of 560 students of four different medical area courses at the University of Milan, enrolled both in the first and in the last course year during the 2017-2018 academic year, were collected.

RESULTS

The prevalence of smokers was 34.8%, almost the same for males and females, and higher in Italian students compared to foreigners. Smoking prevalence was higher among employed (46.9%) than unemployed (35.1%) students, without differences between healthcare and non-healthcare workers. The influence of family, and particularly friends, is confirmed to be relevant. About 25% of respondents tried e-cigarettes, mainly smokers (44.6%) and former smokers (38.6%) with the goal of quitting smoking. More than 44% were dual users of both tobacco cigarettes and e-cigarettes. Comparing smoking habits between first-year and final-year students, only students of healthcare assistance course showed a significant drop in smoking during the university studies.

CONCLUSIONS

The implementation of specific educational curricula on smoking dangers and on smoking cessation techniques might have the double effect of supporting students in quitting smoking and of properly preparing them for their future task of helping people to quit smoking.

Virological and Serological Discordant Profiles in COVID-19 Pneumonia: Two Atypical Clinical Cases

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is primarily diagnosed through viral RNA positivity in nasopharyngeal swabs, and it is associated with the early detection of specific immunoglobulins to SARS-CoV-2 proteins. We describe two moderate coronavirus disease 2019 (COVID-19) patients with WHO score 4/5 at the time of hospitalization, pneumonia, and oxygen saturation <94% and with a strong discrepancy between viral RNA and antibodies to SARS-CoV-2. One patient was positive for viral RNA but completely negative for binding and neutralizing antibodies, whereas the second patient was negative for viral RNA but with high levels of both neutralizing and binding antibodies. This observation is relevant to better understand the pathogenesis of this novel infection.

COVID-19 serological testing for Healthcare Workers in Lombardy, Italy

Issue

COVID-19 pandemic began in Italy on February 20th, 2020. Since the beginning of the emergency Healthcare Workers' (HCWs) involvement was prominent, mainly due to direct assistance to COVID-19 patients. Therefore, we implemented a prevention policy for HCW screening through serological and RT-PCR testing.

Description of the problem

HCW screening for SARS-CoV-2 infection is essential for prevention and control of the pandemic. Lombardy's Healthcare authorities settled a screening process for HCWs divided into three steps: 1) body temperature assessment at the beginning and the end of work shift, if fever > 37.5 °C was present the HCW was sent back home and a nasopharyngeal swab was performed; 2) progressive recruitment for serological testing; 3) on those positive to IgG a nasopharyngeal swab was performed and tested for viral RNA by RT-PCR.

Results

Among 79185 HCW tested, 9589 (12%) were positive on serological IgG testing. Of the 9589 positive a nasopharyngeal swab was performed on 6884. Of these 358 (5%) tested positive and the remaining 6526 (95%) negative to RT-PCR. We calculated a Positive Predictive Value of 5.2%. The rate of positive serological tests for each Healthcare facility varied between 0% and 78%. Five percent of all facilities, belonging to Brescia, Bergamo and Cremona area, reported a positivity rate higher than 40% in HCWs. A second cluster (18% of all facilities), involving the same geographical area, reported a rate between 20% and 40%, whereas the remaining facilities (76%) of the region a rate <20%.

Lessons

Serological IgG testing can be, if followed by immediate nasopharyngeal swab testing, a valid screening intervention on asymptomatic HCWs especially in a high infection prevalence setting.

Key messages

Serological IgG testing can be, if followed by immediate nasopharyngeal swab testing, a valid screening intervention on asymptomatic HCWs.

Infection prevention in HCW may benefit from a screening campaign especially in high prevalence settings.