Haemagglutination inhibition and virus microneutralisation serology assays: use of harmonised protocols and biological standards in seasonal influenza serology testing and their impact on inter-laboratory variation and assay correlation: A FLUCOP collaborative study.

Introduction: The haemagglutination inhibition assay (HAI) and the virus microneutralisation assay (MN) are long-established methods for quantifying antibodies against influenza viruses. Despite their widespread use, both assays require standardisation to improve inter-laboratory agreement in testing. The FLUCOP consortium aims to develop a toolbox of standardised serology assays for seasonal influenza.

Long-Term Serological Investigations of Influenza A Virus in Free-Living Wild Boars () from Northern Italy (2007-2014).

Influenza A viruses (IAV) have been repeatedly demonstrated to circulate in wild suid populations. In this study, serum samples were collected from 2618 free-ranging wild boars in a protected area of Northern Italy between 2007 and 2014, and firstly screened by enzyme-linked immunosorbent assay (ELISA) for the presence of antibodies against IAV. The ELISA-positive samples were further tested by hemagglutination inhibition (HI) assays performed using antigen strains representative of the four major swine IAV (sIAV) lineages circulating in Italy: avian-like swine H1N1, pandemic-like swine H1N1, human-like swine H1N2 and human-like swine H3N2.

Serologic Evidence of Occupational Exposure to Avian Influenza Viruses at the Wildfowl/Poultry/Human Interface.

Ecological interactions between wild aquatic birds and outdoor-housed poultry can enhance spillover events of avian influenza viruses (AIVs) from wild reservoirs to domestic birds, thus increasing the related zoonotic risk to occupationally exposed workers. To assess serological evidence of AIV infection in workers operating in Northern Italy at the wildfowl/poultry interface or directly exposed to wildfowl, serum samples were collected between April 2005 and November 2006 from 57 bird-exposed workers (BEWs) and from 7 unexposed controls (Cs), planning three sample collections from each individual. Concurrently, AIV surveillance of 3587 reared birds identified 4 AIVs belonging to H10N7, H4N6 and H2N2 subtypes while serological analysis by hemagglutination inhibition (HI) assay showed recent infections caused by H1, H2, H4, H6, H10, H11, H12, and H13 subtypes.

Epidemiological characteristics of COVID-19 cases and estimates of the reproductive numbers 1 month into the epidemic, Italy, 28 January to 31 March 2020.

BackgroundOn 20 February 2020, a locally acquired coronavirus disease (COVID-19) case was detected in Lombardy, Italy. This was the first signal of ongoing transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in the country. The number of cases in Italy increased rapidly and the country became the first in Europe to experience a SARS-CoV-2 outbreak.

Whole genome and phylogenetic analysis of two SARS-CoV-2 strains isolated in Italy in January and February 2020: additional clues on multiple introductions and further circulation in Europe.

Whole genome sequences of SARS-CoV-2 obtained from two patients, a Chinese tourist visiting Rome and an Italian, were compared with sequences from Europe and elsewhere. In a phylogenetic tree, the Italian patient's sequence clustered with sequences from Germany while the tourist's sequence clustered with other European sequences. Some additional European sequences in the tree segregated outside the two clusters containing the patients' sequences.

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.

Moderate influenza vaccine effectiveness against A(H1N1)pdm09 virus, and low effectiveness against A(H3N2) subtype, 2018/19 season in Italy.

: Influenza vaccines are updated every year to match the vaccine strains with currently circulating viruses; consequently influenza vaccine effectiveness (IVE) has to be assessed annually.: A test-negative case-control study was conducted within the context of the Italian sentinel influenza surveillance network to estimate IVE by age group, virus subtype, and vaccine brand in medically attended laboratory-confirmed influenza.: In Italy, the 2018/19 influenza season was characterized by the co-circulation of influenza A(H1N1)pdm09 and A(H3N2) viruses.

Virological Surveillance of Influenza in the eight epidemic seasons after the 2009 pandemic in Emilia-Romagna (Northern Italy).

Background And Aim Of The Work: Influenza virological surveillance is essential for monitoring the evolution of influenza viruses (IVs) as well as for annual updating of the vaccine composition. The aim of this study is to analyse IVs circulation in Emilia-Romagna during the eight epidemic seasons after the 2009 pandemic and to evaluate their match with seasonal vaccine strains.

Methods: A total of 7882 respiratory specimens from patients with influenza-like illness (ILI), were collected by regional sentinel practitioners and hospital physicians.

The epidemiological signature of influenza B virus and its B/Victoria and B/Yamagata lineages in the 21st century.

We describe the epidemiological characteristics, pattern of circulation, and geographical distribution of influenza B viruses and its lineages using data from the Global Influenza B Study. We included over 1.8 million influenza cases occurred in thirty-one countries during 2000-2018.

Effectiveness of the trivalent MF59 adjuvated influenza vaccine in preventing hospitalization due to influenza B and A(H1N1)pdm09 viruses in the elderly in Italy, 2017 - 2018 season.

: Evidence on influenza vaccine effectiveness (VE) in preventing mortality and morbidity in the elderly is weak. Our aim was to measure the VE against severe outcomes in the elderly. : We conducted a multicentre hospital-based test-negative design (TND) case-control study, during the 2017/18 season, in four Italian hospitals.

Integrase Defective Lentiviral Vector as a Vaccine Platform for Delivering Influenza Antigens.

Viral vectors represent an attractive technology for vaccine delivery. We exploited the integrase defective lentiviral vector (IDLV) as a platform for delivering relevant antigens within the context of the ADITEC collaborative research program. In particular, Influenza virus hemagglutinin (HA) and nucleoprotein (NP) were delivered by IDLVs while H1N1 A/California/7/2009 subunit vaccine (HAp) with or without adjuvant was used to compare the immune response in a murine model of immunization.

Correction to: Detection and full genome characterization of two beta CoV viruses related to Middle East respiratory syndrome from bats in Italy.

After Publication of the article [1], it has been brought to our attention that an author's name has been spelt incorrectly. The correct spelling should be "Massimo Ciccozzi", but it was previously included as "Massimo Cicozzi". The original version has now been revised to reflect this.

Quantitative Multiplexed Imaging Analysis Reveals a Strong Association between Immunogen-Specific B Cell Responses and Tonsillar Germinal Center Immune Dynamics in Children after Influenza Vaccination.

Generation of Ag-specific humoral responses requires the orchestrated development and function of highly specialized immune cells in secondary lymphoid organs. We used a multiparametric approach combining flow cytometry, confocal microscopy, and histocytometry to analyze, for the first time to our knowledge in children, tonsils from seasonal influenza-vaccinated children. We used these novel imaging assays to address the mucosal immune dynamics in tonsils investigating the spatial positioning, frequency, and phenotype of immune cells after vaccination.

Influenza vaccine effectiveness in Italy: Age, subtype-specific and vaccine type estimates 2014/15 season.

The 2014/15 influenza season in Europe was characterised by the circulation of influenza A(H3N2) viruses with an antigenic and genetic mismatch from the vaccine strain A/Texas/50/2012(H3N2) recommended for the Northern hemisphere for the 2014/15 season. Italy, differently from other EU countries where most of the subtyped influenza A viruses were H3N2, experienced a 2014/15 season characterized by an extended circulation of two influenza viruses: A(H1N1)pdm09 and A(H3N2), that both contributed substantially to morbidity. Within the context of the existing National sentinel influenza surveillance system (InfluNet) a test-negative case-control study was established in order to produce vaccine effectiveness (VE) estimates.

Generation of switched memory B cells in response to vaccination in Down syndrome children and their siblings.

Background: Immunodeficiency is an integral aspect of Down syndrome, as demonstrated by the increased susceptibility to infection of affected. Mortality is still higher than in general population, with respiratory infections among the major causes of death. As more people with Down syndrome are living today than ever before, it is indispensable to develop strategies to prevent and cure the associated disorders.

Human infection with highly pathogenic A(H7N7) avian influenza virus, Italy, 2013.

During an influenza A(H7N7) virus outbreak among poultry in Italy during August-September 2013, infection with a highly pathogenic A(H7N7) avian influenza virus was diagnosed for 3 poultry workers with conjunctivitis. Genetic analyses revealed that the viruses from the humans were closely related to those from chickens on affected farms.

B-sides serologic markers of immunogenicity in kidney transplanted patients: report from 2012-2013 flu vaccination experience.

Background: Safety and immunogenicity data of seasonal influenza vaccination in transplanted patients (Tps) are controversial. Preexisting cross-reactive antibodies generated by repeated vaccination with drift variant strains could bias interpretation of immunogenicity data in Tp.

Methods: The unadjuvanted 2012-2013 seasonal influenza vaccine was administered to 81 kidney Tps being routinely vaccinated against influenza and 23 healthy controls (HCs).

Exploring mucosal immunization with a recombinant influenza virus carrying an HIV-polyepitope in mice with pre-existing immunity to influenza.

HIV-1 vaccines based on recombinant vectors have been developed to elicit immune responses; however, the failure of the STEP HIV-1 vaccine trial has caused concern regarding the impact on vaccine efficacy of pre-existing vector seropositivity in humans. By using a mouse model of infection, we evaluated the immune responses elicited by intranasal and vaginal immunization with the recombinant influenza virus WSN/CKG carrying the PCLUS3-P18 peptide and a Gag epitope in its hemagglutinin, and the impact of pre-existing vector immunity on protection against recombinant vaccinia virus challenge. We found that despite the protective immunity induced in naïve mice by the WSN/CKG virus via either route, the vaginal immunization of mice with pre-existing influenza immunity restricted vPE16 replication more significantly in the ovaries than intranasal immunization.

Antibody but not memory B-cell responses are tuned-down in vertically HIV-1 infected children and young individuals being vaccinated yearly against influenza.

Yearly immunization against seasonal influenza is highly recommended for HIV-1 infected individuals but evaluating the success of vaccination by serological markers may not be fully informative in this population. Recently, it has been hypothesized that the generation of long-lasting immune responses may depend on whether similar antigens challenge the immune system frequently and intermittently. In the present study, in order to search for additional correlates of vaccine-induced protective immunity and to further dissect this theory, both humoral and memory B-cell responses to the trivalent 2012-2013 seasonal influenza vaccination has been evaluated by strain-specific (separately for H1N1, H3N2 and B strain) standard hemagglutination inhibition (HI) assay and B-cell enzyme-linked immunosorbent spot (ELISpot) in a cohort of vertically HIV-1 infected children and young individuals as compared to age-matched healthy controls.

Efficient vagina-to-lower respiratory tract immune trafficking in a murine model of influenza A virus infection.

Effective vaccination strategies for infectious diseases take into account the induction, long-term maintenance and recall of memory T-cell populations. To understand the immunological cross-talk within the mucosal compartments, we compared intranasal to vaginal immunization and demonstrated that vaginal infection of BALB/c mice with influenza A virus provides protective mucosal immunity against both homosubtypic and heterosubtypic virus challenge in the respiratory tract. We found that, prior to the viral challenge, in vaginally primed mice, antigen-specific CD8+ T cells were not detected in the lung airways and levels of serum antibodies were lower than those observed in intranasally immunized mice.