Contribution of respiratory syncytial virus (RSV) among patients <15 years hospitalized with severe acute respiratory infection (SARI) in Milan, 2014-2017

Aim: Respiratory syncytial virus (RSV) infections may range from cold to severe acute respiratory infection (SARI) and are responsible for substantial pediatric morbidity. We describe the results of RSV molecular detection in respiratory samples collected from children <15 years hospitalized with SARI in Milan (Italy) during four consecutive years. Method: From January 1st, 2014, to December 31st, 2017, 3013 respiratory samples (2826 upper-respiratory-tract [UTR] and 187 lower-respiratory-tract [LTR] specimens) collected from as many children <15 years hospitalized with SARI at an University hospital in Milan were analysed. After DNA/RNA extraction, samples were tested by a multiplex real-time PCR to detect RSV and other respiratory viruses. Results: 571 (19%) respiratory samples tested RSV-positive. RSV-positivity rate by sample type was similar (URT vs LRT: 19.2% vs 14.4%; p=0.09). The median age of RSV-positive cases was 6.6 months (inter-quartile range: 17.2 months); 52.2% were males. 62.2% (355/571) of RSV-positive samples were identified in children <1 year and 12.4% (71/571) in those <1 month. RSV was detected throughout the study period; 59.2% (338/571) cases were identified during seasonal peaks (December-February). In 49.9% (285/571) of RSV-positive samples at least another virus (mainly Rhinovirus: 45.9%) was detected, particularly (60%; 171/285) in samples collected from children >1 year. Conclusions: Accordingly to other studies, RSV was detected in 19% of hospitalized-SARI cases <15 years, mainly in children <1 year and in December-February. Sampling of upper or lower airways resulted in similar RSV-positivity rate. Routine molecular testing to detect RSV is warranted to improve clinical management of pediatric patients

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 nextgeneration 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

Analysis of phase patterns in photochromic polyurethanes by a holographic approach

Photochromic polyurethanes based on diarylethene units show a large reversible modulation of refractive index in the Vis-NIR spectral region. The change of refractive index in the material is easily induced by visible laser illumination, without any optical or chemical post-process. In this paper, patterns at the micron scale range have been written by a suitable direct laser writing machine and characterized at 1550 nm by means of a digital holographic approach. The refractive index profile has been retrieved, its dependence on the film thickness and writing speed was shown. The writing process has also been modelled by means of a kinetic model, showing theoretically the dependence of the pattern width and profile on the writing conditions. It is demonstrated that the photochromic films are suitable for developing a reconfigurable platform for complex phase patterns working in the NIR. © 2015 Optical Society of America

Epidemiological and molecular characteristics of HPEV infection in children<6 months hospitalized with symptoms of sepsie-like illness, northen Italy, 2015-2018

BACKGROUND. Human parechoviruses (HPeVs) are widespread pathogens belonging to the Picornaviridae family and currently divided into 19 genotypes. HPeV infections can be associated with severe clinical manifestations, such as sepsis-like illness, particularly in youngest children. The epidemiological and molecular characteristics of HPeV infections observed in children <6 months hospitalized with symptoms of sepsis-like illness were investigated. METHODS. From January 1st, 2015, to December 31st, 2018, clinical samples (cerebrospinal fluid samples and/or blood samples) were collected for diagnosis of HPeV infection from 193 patients (median age: 21 days, range: 1 day - 6 months) hospitalized with symptoms of sepsis-like illness, in two hospitals of Northern Italy. HPeV-RNA was detected by real-time RT-PCR (target 5\u2019UTR) and a portion of HPeV VP3/VP1 junction (nt. 2159\u20132458) was sequenced for typing and molecular characterization. RESULTS. 14% (27/193) of patients with symptoms of sepsis-like illness tested HPeV-positive. 26/27 (96.3%) HPeV-cases were <3 months and 20/27 (74.1%) <1 month. HPeV-positive cases were detected throughout the study period, mainly (12/27; 44.4%) during the summertime (June-August). 17/27 (63%) HPeV-positive samples were molecularly characterized: 16 resulted HPeV-3 and 1 HPeV-5. CONCLUSIONS. HPeV infection was identified in 14% of children <6 months with symptoms of sepsis-like illness. Almost all HPeV infections were detected in children <3 months and mainly during the summertime; almost all molecularly characterized HPeV belonged to type 3. Including HPeV molecular detection in routine diagnostic tests would allow estimating the burden of HPeV infection and improving clinical management of pediatric patients

Influenza Vaccination in Italian Healthcare Workers (2018-2019 Season): Strengths and Weaknesses. Results of a Cohort Study in Two Large Italian Hospitals

Background: Annual vaccination is the most effective way to combat influenza. As influenza viruses evolve, seasonal vaccines are updated annually. Within the European project Development of Robust and Innovative Vaccine Effectiveness (DRIVE), a cohort study involving Italian healthcare workers (HCWs) was carried out during the 2018-2019 season. Two aims were defined: to measure influenza vaccine effectiveness (IVE) against laboratory-confirmed influenza cases and to conduct an awareness-raising campaign to increase vaccination coverage. Methods: Each subject enrolled was followed up from enrollment to the end of the study. Each HCW who developed ILI was swabbed for laboratory confirmation of influenza. Influenza viruses were identified by molecular assays. A Cox regression analysis, crude and adjusted for confounding variables, was performed to estimate the IVE. Results: Among the 4483 HCWs enrolled, vaccination coverage was 32.5%, and 308 ILI cases were collected: 23.4% were positive for influenza (54.2% A(H1N1) pdm09; 45.8% A(H3N2)). No influenza B viruses were detected. No overall IVE was observed. Analyzing the subtypes of influenza A viruses, the IVE was estimated as 45% (95% CI: -59 to 81) for A(H1N1) pdm09. Conclusions: Vaccination coverage among HCWs increased. Study difficulties and the circulation of drifted variants of A(H3N2) could partly explain the observed IVE

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

Genetic analysis of human and swine influenza A viruses isolated in Northern Italy during 2010–2015

Summary Influenza A virus (IAV) infection in swine plays an important role in the ecology of influenza viruses. The emergence of new IAVs comes through different mechanisms, with the genetic reassortment of genes between influenza viruses, also originating from different species, being common. We performed a genetic analysis on 179 IAV isolates from humans (n. 75) and pigs (n. 104) collected in Northern Italy between 2010 and 2015, to monitor the genetic exchange between human and swine IAVs. No cases of human infection with swine strains were noticed, but direct infections of swine with H1N1pdm09 strains were detected. Moreover, we pointed out a continuous circulation of H1N1pdm09 strains in swine populations evidenced by the introduction of internal genes of this subtype. These events contribute to generating new viral variants—possibly endowed with pandemic potential—and emphasize the importance of continuous surveillance at both animal and human level

Co-circulation of the two influenza B lineages during 13 consecutive influenza surveillance seasons in Italy, 2004-2017

BACKGROUND: Since 1985, two antigenically distinct lineages of influenza B viruses (Victoria-like and Yamagata-like) have circulated globally. Trivalent seasonal influenza vaccines contain two circulating influenza A strains but a single B strain and thus provide limited immunity against circulating B strains of the lineage not included in the vaccine. In this study, we describe the characteristics of influenza B viruses that caused respiratory illness in the population in Italy over 13 consecutive seasons of virological surveillance, and the match between the predominant influenza B lineage and the vaccine B lineage, in each season. METHODS: From 2004 to 2017, 26,886 laboratory-confirmed influenza cases were registered in Italy, of which 18.7% were type B. Among them, the lineage of 2465 strains (49%) was retrieved or characterized in this study by a real-time RT-PCR assay and/or sequencing of the hemagglutinin (HA) gene. RESULTS: Co-circulation of both B lineages was observed each season, although in different proportions every year. Overall, viruses of B/Victoria and B/Yamagata lineages caused 53.3 and 46.7% of influenza B infections, respectively. A higher proportion of infections with both lineages was detected in children, and there was a declining frequency of B/Victoria detections with age. A mismatch between the vaccine and the predominant influenza B lineage occurred in eight out of thirteen influenza seasons under study. Considering the seasons when B accounted for &gt;\u200920% of all laboratory-confirmed influenza cases, a mismatch was observed in four out of six seasons. Phylogenetic analysis of the HA1 domain confirmed the co-circulation of both lineages and revealed a mixed circulation of distinct evolutionary viral variants, with different levels of match to the vaccine strains. CONCLUSIONS: This study contributes to the understanding of the circulation of influenza B viruses in Italy. We found a continuous co-circulation of both B lineages in the period 2004-2017, and determined that children were particularly vulnerable to Victoria-lineage influenza B virus infections. An influenza B lineage mismatch with the trivalent vaccine occurred in about two-thirds of cases

Segregation of Virulent Influenza A(H1N1) Variants in the Lower Respiratory Tract of Critically Ill Patients during the 2010–2011 Seasonal Epidemic

BACKGROUND: Since its appearance in 2009, the pandemic influenza A(H1N1) virus circulated worldwide causing several severe infections. METHODS: Respiratory samples from patients with 2009 influenza A(H1N1) and acute respiratory distress attending 24 intensive care units (ICUs) as well as from patients with lower respiratory tract infections not requiring ICU admission and community upper respiratory tract infections in the Lombardy region (10 million inhabitants) of Italy during the 2010-2011 winter-spring season, were analyzed. RESULTS: In patients with severe ILI, the viral load was higher in bronchoalveolar lavage (BAL) with respect to nasal swab (NS), (p<0.001) suggesting a higher virus replication in the lower respiratory tract. Four distinct virus clusters (referred to as cluster A to D) circulated simultaneously. Most (72.7%, n = 48) of the 66 patients infected with viruses belonging to cluster A had a severe (n = 26) or moderate ILI (n = 22). Amino acid mutations (V26I, I116M, A186T, D187Y, D222G/N, M257I, S263F, I286L/M, and N473D) were observed only in patients with severe ILI. D222G/N variants were detected exclusively in BAL samples. CONCLUSIONS: Multiple virus clusters co-circulated during the 2010-2011 winter-spring season. Severe or moderate ILI were associated with specific 2009 influenza A(H1N1) variants, which replicated preferentially in the lower respiratory tract

Emergence of divergent enterovirus (EV) D68 sub-clade D1 strains, northern Italy, September to October 2018

An enterovirus D68 (EV-D68) outbreak was recognised at a major tertiary centre and research hospital in Milan and Pavia in the Lombardy region, northern Italy, respectively, between September and October 2018. Here, we present the molecular and clinical characteristics of the confirmed EV-D68 cases detected during the outbreak sustained by EV-D68 sub-clade D1 strains