Transmission of Hemagglutinin D222G Mutant Strain of Pandemic (H1N1) 2009 Virus

A pandemic (H1N1) 2009 virus strain carrying the D222G mutation was identified in a severely ill man and was transmitted to a household contact. Only mild illness developed in the contact, despite his obesity and diabetes. The isolated virus reacted fully with an antiserum against the pandemic vaccine strain

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. In order to maximize the antibody response against HA, both IDLVs were also pseudotyped with HA (IDLV-HA/HA and IDLV-NP/HA, respectively). Groups of CB6F1 mice were immunized intramuscularly with a single dose of IDLV-NP/HA, IDLV-HA/HA, HAp alone or with HAp together with the systemic adjuvant MF59. Six months after the vaccine prime all groups were boosted with HAp alone. Cellular and antibody responses to influenza antigens were measured at different time points after the immunizations. Mice immunized with HA-pseudotyped IDLVs showed similar levels of anti-H1N1 IgG over time, evaluated by ELISA, which were comparable to those induced by HAp+MF59 vaccination, but significantly higher than those induced by HAp alone. The boost with HAp alone induced an increase of antibodies in all groups, and the responses were maintained at higher levels up to 18 weeks post-boost. The antibody response was functional and persistent overtime, capable of neutralizing virus infectivity, as evaluated by hemagglutination inhibition and microneutralization assays. Moreover, since neuraminidase (NA)-expressing plasmid was included during IDLV preparation, immunization with IDLV-NP/HA and IDLV-HA/HA also induced functional anti-NA antibodies, evaluated by Enzyme-Linked Lectine Assay (ELLA). IFN?-ELISPOT showed evidence of HA-specific response in IDLV-HA/HA immunized animals and persistent NP-specific CD8+ T cell response in IDLV-NP/HA immunized mice. Taken together our results indicate that IDLV can be harnessed for producing a vaccine able to induce a comprehensive immune response, including functional antibodies directed towards HA and NA proteins present on the vector particles in addition to a functional T cell response directed to the protein transcribed from the vector

Centro Nazionale Influenza. Sorveglianza virologica dell'influenza in Italia. Rapporto preliminare

Consiglio Nazionale delle Ricerche - Biblioteca Centrale - P.le Aldo Moro, 7 Rome / CNR - Consiglio Nazionale delle RichercheSIGLEITItal

Characterization of an influenza B virus isolated from a fatal case of myocarditis in a pediatric patient in Italy

Influenza B is one of the infective agents that can cause rapid and fatal myocarditis in children. Here, we describe a fatal case of myocarditis in a previously healthy child, after infection with an influenza B/Victoria-lineage virus during the 2022–23 epidemic season in Italy. Influenza B virus was isolated also in a second case, a younger family member showing only a mild influenza-like illness. Genotypic and phenotypic analyses have been performed on both virus samples and results showed that HA1 sequences were identical and genetically and antigenically related to other B viruses circulating in 2022–23 season in Italy. However, a D129N substitution was found in the receptor binding domain of the HA of the two viruses, not detected in other circulating viruses in Italy but only in a proportion of those circulating in other European countries. Phenotypic analyses assessed the susceptibility towards either neuraminidase inhibitors and baloxavir. Annual influenza vaccination remains one of the best interventions to prevent complications such as myocarditis, particularly in children

Evidence of cross-reactive immunity to 2009 pandemic influenza A virus in workers seropositive to swine H1N1 influenza viruses circulating in Italy.

BACKGROUND: Pigs play a key epidemiologic role in the ecology of influenza A viruses (IAVs) emerging from animal hosts and transmitted to humans. Between 2008 and 2010, we investigated the health risk of occupational exposure to swine influenza viruses (SIVs) in Italy, during the emergence and spread of the 2009 H1N1 pandemic (H1N1pdm) virus. METHODOLOGY/PRINCIPAL FINDINGS: Serum samples from 123 swine workers (SWs) and 379 control subjects (Cs), not exposed to pig herds, were tested by haemagglutination inhibition (HI) assay against selected SIVs belonging to H1N1 (swH1N1), H1N2 (swH1N2) and H3N2 (swH3N2) subtypes circulating in the study area. Potential cross-reactivity between swine and human IAVs was evaluated by testing sera against recent, pandemic and seasonal, human influenza viruses (H1N1 and H3N2 antigenic subtypes). Samples tested against swH1N1 and H1N1pdm viruses were categorized into sera collected before (n. 84 SWs; n. 234 Cs) and after (n. 39 SWs; n. 145 Cs) the pandemic peak. HI-antibody titers ≥10 were considered positive. In both pre-pandemic and post-pandemic peak subperiods, SWs showed significantly higher swH1N1 seroprevalences when compared with Cs (52.4% vs. 4.7% and 59% vs. 9.7%, respectively). Comparable HI results were obtained against H1N1pdm antigen (58.3% vs. 7.7% and 59% vs. 31.7%, respectively). No differences were found between HI seroreactivity detected in SWs and Cs against swH1N2 (33.3% vs. 40.4%) and swH3N2 (51.2 vs. 55.4%) viruses. These findings indicate the occurrence of swH1N1 transmission from pigs to Italian SWs. CONCLUSION/SIGNIFICANCE: A significant increase of H1N1pdm seroprevalences occurred in the post-pandemic peak subperiod in the Cs (p<0.001) whereas SWs showed no differences between the two subperiods, suggesting a possible occurrence of cross-protective immunity related to previous swH1N1 infections. These data underline the importance of risk assessment and occupational health surveillance activities aimed at early detection and control of SIVs with pandemic potential in humans

Immunogenicity of Viral Vaccines in the Italian Military

Military personnel of all armed forces receive multiple vaccinations and have been doing so since long ago, but relatively few studies have investigated the possible negative or positive interference of simultaneous vaccinations. As a contribution to fill this gap, we analyzed the response to the live trivalent measles/mumps/rubella (MMR), the inactivated hepatitis A virus (HAV), the inactivated trivalent polio, and the trivalent subunits influenza vaccines in two cohorts of Italian military personnel. The first cohort was represented by 108 students from military schools and the second by 72 soldiers engaged in a nine-month mission abroad. MMR and HAV vaccines had never been administered before, whereas inactivated polio was administered to adults primed at infancy with a live trivalent oral polio vaccine. Accordingly, nearly all subjects had baseline antibodies to polio types 1 and 3, but unexpectedly, anti-measles/-mumps/-rubella antibodies were present in 82%, 82%, and 73.5% of subjects, respectively (43% for all of the antigens). Finally, anti-HAV antibodies were detectable in 14% and anti-influenza (H1/H3/B) in 18% of the study population. At mine months post-vaccination, 92% of subjects had protective antibody levels for all MMR antigens, 96% for HAV, 69% for the three influenza antigens, and 100% for polio types 1 and 3. An inverse relationship between baseline and post-vaccination antibody levels was noticed with all the vaccines. An excellent vaccine immunogenicity, a calculated long antibody persistence, and apparent lack of vaccine interference were observed

HI antibody reactivity against swH1N1 and H1N1pdm viruses in Cs (Italy, 2008–2010).

<p>Serum samples were collected from control subjects (Cs) in the pre-pandemic peak (15 December 2008–1 November 2009) and post-pandemic peak (2 November 2009–3 October 2010) periods and tested by haemagglutination inhibition (HI) assay. Individual HI results referred to the three cutoff levels (≥10, ≥20 and ≥40) chosen for the statistical analysis of data, and ranging from 10 (minimum level of detection) to 40 (protective antibody titer). A significant increase in seroprevalence rate (SPR) was found against swH1N1 at cutoff ≥20 (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0057576#pone-0057576-g002" target="_blank">Figure 2A</a>), whereas H1N1pdm SPRs (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0057576#pone-0057576-g002" target="_blank">Figure 2B</a>) were significantly higher in the post-pandemic peak period, at all cutoff titer levels (viruses details and SPRs are shown in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0057576#pone-0057576-t005" target="_blank">Table 5</a>). SPR significant difference (p<0.05).</p

HI antibody reactivity of SWs and Cs sera against swine and human influenza viruses during the whole study period (Italy, 2008–2010)^§.

§<p>Values are no. persons with antibodies.</p>∧<p>Data adjusted by age in binary logistic regression.</p><p>HI, Haemagglutination inhibition.</p><p>SWs, swine workers; Cs, controls.</p><p>OR, odds ratio; CI, confidence interval; nc, not calculated.</p><p>swH1N1, A/Swine/Italy/44795/08; huH1N1pdm, A/California/7/09;</p><p>swH1N2, A/Swine/Italy/114347–1/06; huH1N1, A/Brisbane/59/07;</p><p>swH3N2, A/Swine/Italy/32242/06; huH3N2, A/Uruguay/716/07.</p><p>Statistically significant values: *, p<0.05; **, p<0.01; ***, p<0.001.</p