Dataset Information

Seasonal Influenza A H1N1pdm09 Virus and Severe Outcomes: A Reason for Broader Vaccination in Non-Elderly, At-Risk People.

ABSTRACT:

Background

Recent pandemics of influenza A H1N1pdm09 virus have caused severe illness, especially in young people. Very few studies on influenza A H1N1pdm09 in post-pandemic periods exist, and there is no information on the severity of both seasonal influenza A(H1N1) and A(H3N2) from the same season, adjusting for potential confounders, including vaccine.

Methods and results

We performed a retrospective observational study of adults hospitalized during the 2014 season with influenza A(H1N1) or A(H3N2). All patients underwent the same diagnostic and therapeutic protocol in a single hospital, including early Oseltamivir therapy. We included 234 patients: 146 (62.4%) influenza A(H1N1) and 88 (37.6%) A(H3N2). A(H1N1) patients were younger (p<0.01), developed more pneumonia (p<0.01), respiratory complications (p = 0.015), ARDS (p = 0.047), and septic shock (p = 0.049), were more frequently admitted to the ICU (p = 0.022), required IMV (p = 0.049), and were less frequently vaccinated (p = 0.008). After adjusting for age, comorbidities, time from onset of illness, and vaccine status, influenza A(H1N1) (OR, 2.525), coinfection (OR, 2.821), and no vaccination (OR, 3.086) were independent risk factors for severe disease.

Conclusions

Hospitalized patients with influenza A(H1N1) were more than twice as likely to have severe influenza. They were younger and most had not received the vaccine. Our findings suggest that seasonal influenza A(H1N1) maintains some features of pandemic viruses, and recommend wider use of vaccination in younger adult high-risk patients.

SUBMITTER: Minchole E

PROVIDER: S-EPMC5104455 | biostudies-literature | 2016

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Seasonal Influenza A H1N1pdm09 Virus and Severe Outcomes: A Reason for Broader Vaccination in Non-Elderly, At-Risk People.

Minchole Elisa E Figueredo Ana L AL Omeñaca Manuel M Panadero Carolina C Royo Laura L Vengoechea Jose J JJ Fandos Sergio S de Pablo Francisco F Bello Salvador S

PloS one 20161110 11

<h4>Background</h4>Recent pandemics of influenza A H1N1pdm09 virus have caused severe illness, especially in young people. Very few studies on influenza A H1N1pdm09 in post-pandemic periods exist, and there is no information on the severity of both seasonal influenza A(H1N1) and A(H3N2) from the same season, adjusting for potential confounders, including vaccine.<h4>Methods and results</h4>We performed a retrospective observational study of adults hospitalized during the 2014 season with influen ...[more]

PMID: 27832114

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Project description:Antibodies to influenza surface protein neuraminidase (NA) have been found to reduce disease severity and may be an independent correlate of protection. Despite this, current influenza vaccines have no regulatory requirements for the quality or quantity of the NA antigen and are not optimized for induction of NA-specific antibodies. Here we investigate the induction and durability of NA-specific antibody titers after pandemic AS03-adjuvanted monovalent H1N1 vaccination and subsequent annual vaccination in health care workers in a five-year longitudinal study. NA-specific antibodies were measured by endpoint ELISA and functional antibodies measured by enzyme-linked lectin assay (ELLA) and plaque reduction naturalisation assay. We found robust induction of NA inhibition (NAI) titers with a 53% seroconversion rate (>4-fold) after pandemic vaccination in 2009. Furthermore, the endpoint and NAI geometric mean titers persisted above pre-vaccination levels up to five years after vaccination in HCWs that only received the pandemic vaccine, which demonstrates considerable durability. Vaccination with non-adjuvanted trivalent influenza vaccines (TIV) in subsequent influenza seasons 2010/2011 – 2013/2014 further boosted NA-specific antibody responses. We found that each subsequent vaccination increased durable endpoint titers and contributed to maintaining the durability of functional antibody titers. Although the trivalent influenza vaccines boosted NA-specific antibodies, the magnitude of fold-increase at day 21 declined with repeated vaccination, particularly for functional antibody titers. High levels of pre-existing antibodies were associated with lower fold-induction in repeatedly vaccinated HCWs. In summary, our results show that durable NA-specific antibody responses can be induced by an adjuvanted influenza vaccine, which can be maintained and further boosted by TIVs. Although NA-specific antibody responses are boosted by annual influenza vaccines, high pre-existing titers may negatively affect the magnitude of fold-increase in repeatedly vaccinated individuals. Our results support continued development and standardization of the NA antigen to supplement current influenza vaccines and reduce the burden of morbidity and mortality.

Project description:Background/objectivesDespite influenza vaccination programs in various jurisdictions, seasonal influenza vaccine (SIV) uptake remains suboptimal among older people (≥65years old), an important subpopulation for influenza vaccination. We sought to summarize determinants of SIV uptake (any vaccine receipt) and vaccination adherence (receipt of vaccine in two or more seasons in sequence) among older people.MethodsWe searched for population-based studies conducted in community-dwelling older people (irrespective of their health status) from 2000-2019. Two reviewers independently selected publications for inclusion. One reviewer extracted data from the included studies; a second checked the extracted data for errors. Disagreements were resolved by discussion and consensus, or a third reviewer. We were interested in the determinants of SIV uptake and vaccination adherence. Where appropriate, we pooled adjusted results using the inverse variance, random-effects method and reported the odds ratios (OR) and their 95% confidence intervals (CI).ResultsOut of 11,570 citations screened, we included 34 cross-sectional studies. The following were associated with increased SIV uptake: being older (OR 1.52, 95%CI 1.38-1.67 [21 studies]), white (1.30, 1.14-1.49 [10 studies]), married (1.23, 1.17-1.28 [9 studies]), non-smoker (1.28, 1.11-1.47 [7 studies]), of a higher social class (1.20, 1.06-1.36 [2 studies]), having a higher education (1.12, 1.04-1.21 [14 studies]), having a higher household income (1.11, 1.05-1.18 [8 studies]), having a chronic illness (1.53, 1.44-1.63 [16 studies]), having poor self-assessed health (1.23, 1.02-1.40 [9 studies]), having a family doctor (2.94, 1.79-4.76 [2 studies]), and having health insurance (1.58, 1.13-2.21 [6 studies]). The influence of these factors varied across geographical regions. Being older (1.26, 1.11-1.44 [2 studies]) was also associated with increased vaccination adherence.ConclusionsSeveral factors may determine SIV uptake and vaccination adherence among older people. More studies are needed to provide a stronger evidence base for planning more effective influenza vaccination programs.

Dataset Information

Seasonal Influenza A H1N1pdm09 Virus and Severe Outcomes: A Reason for Broader Vaccination in Non-Elderly, At-Risk People.

Background

Methods and results

Conclusions

Publications

Seasonal Influenza A H1N1pdm09 Virus and Severe Outcomes: A Reason for Broader Vaccination in Non-Elderly, At-Risk People.

Similar Datasets

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