Burden of seasonal influenza in the Swiss adult population during the 2016/2017–2018/2019 influenza seasons
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ABSTRACT:
SUBMITTER: Ammann D
PROVIDER: S-EPMC10667819 | biostudies-literature | 2023 Nov
REPOSITORIES: biostudies-literature
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Project description:BackgroundHere, we genetically and antigenically analyzed influenza B viruses (IBVs) isolated in Japan during the 2017-2018 and 2018-2019 influenza seasons.MethodsA total of 68 IBVs (61 B/Yamagata/16/88-like [B/Yamagata]-lineage and 7 B/Victoria/2/87-like [B/Victoria]-lineage) were antigenically and genetically characterized by using hemagglutination inhibition (HI) assays and phylogenetic analysis, respectively. The susceptibility of IBVs to neuraminidase (NA) inhibitors was assessed by using a fluorescence-based NA inhibition assay.ResultsAll 61 B/Yamagata-lineage isolates were genetically closely related to B/Phuket/3073/2013, the vaccine strain for these two seasons. Eleven B/Yamagata-lineage isolates tested were antigenically similar to B/Phuket/3073/2013 by the HI test. Seven B/Victoria-lineage isolates were genetically closely related to B/Texas/02/2013, the WHO-recommended vaccine strain for the 2017-2018 season; however, they were antigenically distinct from B/Texas/02/2013 with an eightfold or 16-fold difference in HI titer. Of these 7 isolates, 4 possessed a two-amino-acid deletion at positions 162 and 163 in hemagglutinin (HA) and the other 3 had a three-amino-acid deletion at positions 162-164 in HA. Importantly, the variants with the three-amino-acid deletion appeared to be antigenically different from the B/Colorado/06/2017 virus with the two-amino-acid deletion, the vaccine strain for the 2018-2019 season with a fourfold or eightfold difference in HI titer. One B/Yamagata-lineage isolate carrying a G407S mutation in its NA showed a marked reduction in susceptibility to zanamivir, peramivir, and laninamivir.ConclusionsThese results highlight the need for continued monitoring for the prevalence of the antigenic variant with the three-amino-acid deletion and the variant with reduced NA inhibitor susceptibility.
| S-EPMC7182600 | biostudies-literature
Project description:BackgroundThe (H1N1)pdm09 live attenuated influenza vaccine (LAIV) strain was changed for the 2017-2018 influenza season to improve viral fitness, following poor protection against (H1N1)pdm09 viruses in 2015-2016. We conducted LAIV virus shedding studies to assess the effect of this change.MethodsChildren aged 2-18 years were recruited to receive LAIV in the 2016-2017 (n = 641) and 2017-2018 (n = 362) influenza seasons. Viruses from nasal swabs taken 1, 3, and 6 days postvaccination were quantified by reverse-transcription polymerase chain reaction and area under the curve titers were determined. Presence and quantity of shedding were compared between strains and seasons with adjustment for age and prior LAIV (n = 436), inactivated seasonal vaccine (n = 100), or (H1N1)pdm09 vaccine (n = 166) receipt.Results(H1N1)pdm09 detection (positivity) in 2016-2017 and 2017-2018 (11.2% and 3.9%, respectively) was lower than that of H3N2 (19.7% and 18.7%, respectively) and B/Victoria (28.9% and 33.9%, respectively). (H1N1)pdm09 positivity was higher in 2016-2017 than 2017-2018 (P = .005), but within shedding-positive participants, the (H1N1)pdm09 titer increased in 2017-2018 (P = .02). H3N2 and influenza B titers were similar between seasons. Positivity declined with age, and prior vaccination reduced the likelihood of shedding influenza B but not (H1N1)pdm09.ConclusionsThe (H1N1)pdm09 titer increased in 2017-2018, indicating more efficient virus replication in shedding-positive children than the 2016-2017 strain, although overall positivity was reduced. Age and vaccination history require consideration when correlating virus shedding and protection.Clinical trials registrationNCT02143882, NCT02866942, and NCT03104790.
| S-EPMC7286380 | biostudies-literature
Project description:BackgroundEvidence for vaccine effectiveness (VE) against influenza-associated pneumonia has varied by season, location, and strain. We estimate VE against hospitalization for radiographically identified influenza-associated pneumonia during 2015-2016 to 2017-2018 seasons in the US Hospitalized Adult Influenza Vaccine Effectiveness Network (HAIVEN).MethodsAmong adults aged ≥18 years admitted to 10 US hospitals for acute respiratory illness (ARI), clinician-investigators used keywords from reports of chest imaging performed during 3 days around hospital admission to assign a diagnosis of "definite/probable pneumonia." We used a test-negative design to estimate VE against hospitalization for radiographically identified laboratory-confirmed influenza-associated pneumonia, comparing reverse transcriptase-polymerase chain reaction-confirmed influenza cases with test-negative subjects. Influenza vaccination status was documented in immunization records or self-reported, including date and location. Multivariable logistic regression models were used to adjust for age, site, season, calendar-time, and other factors.ResultsOf 4843 adults hospitalized with ARI included in the primary analysis, 266 (5.5%) had "definite/probable pneumonia" and confirmed influenza. Adjusted VE against hospitalization for any radiographically confirmed influenza-associated pneumonia was 38% (95% confidence interval [CI], 17-53%); by type/subtype, it was 74% (95% CI, 52-87%) influenza A (H1N1)pdm09, 25% (95% CI, -15% to 50%) A (H3N2), and 23% (95% CI, -32% to 54%) influenza B. Adjusted VE against intensive care for any influenza was 57% (95% CI, 19-77%).ConclusionsInfluenza vaccination was modestly effective among adults in preventing hospitalizations and the need for intensive care associated with influenza pneumonia. VE was significantly higher against A (H1N1)pdm09 and was low against A (H3N2) and B.
| S-EPMC9049268 | biostudies-literature
Project description:A test-negative case-control study was conducted to assess inactivated influenza vaccine effectiveness (VE) in children aged 6 months-17 years. The database was developed from the US Department of Defense Global Respiratory Pathogen Surveillance Program over four consecutive influenza seasons from 2016 to 2020. A total of 9,385 children including 4,063 medically attended, laboratory-confirmed influenza-positive cases were identified for VE analysis. A generalized linear mixed model with logit link and binomial distribution was used to estimate the VE. The adjusted VE for children was 42% [95% confidence interval (CI): 37-47%] overall, including 55% (95% CI: 47-61%) for influenza A(H1N1)pdm09, 37% (95% CI: 28-45%) for influenza A(H3N2), and 49% (95% CI: 41-55%) for influenza B. The analysis by age groups indicated that the adjusted VE in children aged 6 months-4 years was higher against influenza A(H1N1)pdm09 and influenza B, and comparable against influenza A(H3N2), compared to those in children aged 5-17 years. Further age-stratified analysis showed that the VE against any types of influenza was low and non-significant for children aged 6-11 months (33%; 95% CI:-2-56%), but it was high (54%; 95% CI: 34-67%) in children aged 12-23 months, and then declined linearly with increasing age. In conclusion, the inactivated influenza vaccination was moderately effective against influenza infection, based on the analysis from a large number of children aged 6 months-17 years over multiple influenza seasons.
| S-EPMC8397503 | biostudies-literature
Project description:BackgroundEstimating the global burden of influenza hospitalizations is required to allocate resources and assess interventions that aim to prevent severe influenza. In France, the current routine influenza surveillance system does not fully measure the burden of severe influenza cases. The objective was to describe the characteristics and severity of influenza hospitalizations by age-group and by season between 2012 and 2017.MethodsAll hospitalizations with a diagnosis of influenza in metropolitan France between July 2012 and June 2017 were extracted from the French national hospital discharge database (PMSI). For each season, the total number of influenza hospitalizations, admissions to intensive care units (ICU), proportion of deaths, lengths of stay, and distribution in diagnosis-related groups were described by age-group.ResultsOver the five seasons, 91 255 hospitalizations with a diagnosis of influenza were identified. The average influenza hospitalization rate varied from 13/100 000 in 2013-2014 to 46/100 000 in 2016-2017. A high rate was observed in elderlies during the 2014-2015 and 2016-2017 seasons, dominated by A(H3N2) virus. The youngest were impacted in 2015-2016, dominated by B/Victoria virus. The proportion of influenza hospitalizations with ICU admission was 10%, and was higher in age-group 40-79 years. The proportion of deaths and length of stay increased with age.ConclusionsThe description of influenza hospitalizations recorded in the PMSI give key information on the burden of severe influenza in France. Analyses of these data annually is valuable in order to document the severity of influenza hospitalizations by age-group and according to the circulating influenza viruses.
| S-EPMC7182605 | biostudies-literature
Project description:The 2017-2018 influenza epidemic season in Russia was characterized by a relatively low morbidity and mortality. We evaluated herd immunity prior to the 2017-2018 influenza season in hemagglutination inhibition assay, and performed characterization of influenza viruses isolated from severe or fatal influenza cases and from influenza cases in people vaccinated in the fall of 2017. During the 2017-2018 epidemic season, 87 influenza A and B viruses were isolated and viruses of the 75 influenza cases, including selected viral isolates and viruses analyzed directly from the original clinical material, were genetically characterized. The analyzed A(H1N1)pdm09 viruses belonged to clade 6B.1, B/Yamagata-like viruses belonged to clade 3, and B/Victoria-like viruses belonged to clade 1A and they were antigenically similar to the corresponding vaccine strains. A(H3N2) viruses belonged to clade 3C.2a and were difficult to characterize antigenically and the analysis indicated antigenic differences from the corresponding egg-grown vaccine strain. The next generation sequencing revealed the presence of D222/G/N polymorphism in the hemagglutinin gene in 32% of the analyzed A(H1N1)pdm09 lethal cases. This study demonstrated the importance of monitoring D222G/N polymorphism, including detection of minor viral variants with the mutations, in the hemagglutinin gene of A(H1N1)pdm09 for epidemiological surveillance. One strain of influenza virus A(H1N1)pdm09 was resistant to oseltamivir and had the H275Y amino acid substitution in the NA protein. All other isolates were susceptible to NA inhibitors. Prior to the 2017-2018 epidemic season, 67.4 million people were vaccinated, which accounted for 46.6% of the country's population. Just before the epidemic season 33-47% and 24-30% of blood sera samples collected within the territory of Russia showed the presence of protective antibody titers against vaccine strains of influenza A and influenza B/Victoria-like, respectively. Mass vaccination of the population had evidently reduced the severity of the flu epidemic during the 2017-2018 influenza epidemic season in Russia.
| S-EPMC6663013 | biostudies-literature
Project description:The objective of this study was to apply the multi-agent system (MAS) collision model to predict seasonal influenza epidemic in Tokyo for 5 seasons (2014-2015 to 2018-2019 seasons). The MAS collision model assumes each individual as a particle inside a square domain. The particles move within the domain and disease transmission occurs in a certain probability when an infected particle collides a susceptible particle. The probability was determined based on the basic reproduction number calculated using the actual data. The simulation started with 1 infected particle and 999 susceptible particles to correspond to the onset of an influenza epidemic. We performed the simulation for 150 days and the calculation was repeated 500 times for each season. To improve the accuracy of the prediction, we selected simulations which have similar incidence number to the actual data in specific weeks. Analysis including all simulations corresponded good to the actual data in 2014-2015 and 2015-2016 seasons. However, the model failed to predict the sharp peak incidence after the New Year Holidays in 2016-2017, 2017-2018, and 2018-2019 seasons. A model which included simulations selected by the week of peak incidence predicted the week and number of peak incidence better than a model including all simulations in all seasons. The reproduction number was also similar to the actual data in this model. In conclusion, the MAS collision model predicted the epidemic curve with good accuracy by selecting the simulations using the actual data without changing the initial parameters such as the basic reproduction number and infection time.
| S-EPMC8391024 | biostudies-literature
Project description:BackgroundThe 2016-2017 and 2017-2018 influenza seasons were notable for the high number of hospitalizations for influenza A(H3N2) despite vaccine and circulating strain match.MethodsWe evaluated vaccine effectiveness (VE) against hospitalization in the test-negative HAIVEN study. Nasal-throat swabs were tested by quantitative reverse transcription polymerase chain reaction (RT-PCR) for influenza and VE was determined based on odds of vaccination by generalized estimating equations. Vaccine-specific antibody was measured in a subset of enrollees.ResultsA total of 6129 adults were enrolled from 10 hospitals. Adjusted VE against A(H3N2) was 22.8% (95% confidence interval [CI], 8.3% to 35.0%), pooled across both years and 49.4% (95% CI, 34.3% to 61.1%) against B/Yamagata. In 2017-2018, the A(H3N2) VE point estimate for the cell-based vaccine was 43.0% (95% CI, -36.3% to 76.1%; 56 vaccine recipients) compared to 24.0% (95% CI, 3.9% to 39.9%) for egg-based vaccines. Among 643 with serology data, hemagglutinin antibodies against the egg-based A(H3N2) vaccine strain were increased in influenza-negative individuals.ConclusionsLow VE for the A/Hong Kong/4801/2014 vaccine virus in both A(H3N2) seasons emphasizes concerns for continued changes in H3N2 antigenic epitopes, including changes that may impact glycosylation and ultimately reduce VE.
| S-EPMC8205618 | biostudies-literature
Project description:The influenza A(H1N1)pdm09 virus that emerged in 2009 causes seasonal epidemic worldwide. The virus acquired several amino acid substitutions that were responsible for antigenic drift until the 2018-2019 influenza season. Viruses possessing mutations in the NA and PA proteins that cause reduced susceptibility to NA inhibitors and baloxavir marboxil, respectively, have been detected after antiviral treatment, albeit infrequently. Here, we analyzed HA, NA, and PA sequences derived from A(H1N1)pdm09 viruses that were isolated during the 2018-2019 and 2019-2020 influenza seasons in Japan. We found that A(H1N1)pdm09 viruses possessing the D187A and Q189E substitutions in HA emerged and dominated during the 2019-2020 season; these substitutions in the antigenic site Sb, a high potency neutralizing antibody-eliciting site for humans, changed the antigenicity of A(H1N1)pdm09 viruses. Furthermore, we found that isolates possessing the N156K substitution, which was predicted to affect the antigenicity of A(H1N1)pdm09 virus at the laboratory level, were detected at a frequency of 1.0% in the 2018-2019 season but 10.1% in the 2019-2020 season. These findings indicate that two kinds of antigenically drifted viruses-N156K and D187A/Q189E viruses-co-circulated during the 2019-2020 influenza season in Japan.
| S-EPMC9968111 | biostudies-literature
Project description:[This corrects the article DOI: 10.1371/journal.pone.0220401.].
| S-EPMC6934315 | biostudies-literature