Dataset Information

Antibody Responses to Influenza A/H1N1pdm09 Virus After Pandemic and Seasonal Influenza Vaccination in Healthcare Workers: A 5-Year Follow-up Study.

ABSTRACT: Background:The 2009 influenza pandemic was caused by the A/H1N1pdm09 virus, which was subsequently included in the seasonal vaccine, up to 2016/2017, as the A/H1N1 strain. This provided a unique opportunity to investigate the antibody response to H1N1pdm09 over time. Methods:Healthcare workers (HCWs) were immunized with the AS03-adjuvanted H1N1pdm09 vaccine in 2009 (N = 250), and subsequently vaccinated with seasonal vaccines containing H1N1pdm09 for 4 seasons (repeated group), <4 seasons (occasional group), or no seasons (single group). Blood samples were collected pre and at 21 days and 3, 6, and 12 months after each vaccination, or annually (pre-season) from 2010 in the single group. The H1N1pdm09-specific antibodies were measured by the hemagglutination inhibition (HI) assay. Results:Pandemic vaccination robustly induced HI antibodies that persisted above the 50% protective threshold (HI titers ? 40) over 12 months post-vaccination. Previous seasonal vaccination and the duration of adverse events after the pandemic vaccination influenced the decision to vaccinate in subsequent seasons. During 2010/2011-2013/2014, antibodies were boosted after each seasonal vaccination, although no significant difference was observed between the repeated and occasional groups. In the single group without seasonal vaccination, 32% of HCWs seroconverted (?4-fold increase in HI titers) during the 4 subsequent years, most of whom had HI titers <40 prior to seroconversion. When excluding these seroconverted HCWs, HI titers gradually declined from 12 to 60 months post-pandemic vaccination. Conclusions:Pandemic vaccination elicited durable antibodies, supporting the incorporation of adjuvant. Our findings support the current recommendation of annual influenza vaccination in HCWs. Clinical Trials Registration:NCT01003288.

SUBMITTER: Trieu MC

PROVIDER: S-EPMC6336911 | biostudies-literature | 2019 Jan

REPOSITORIES: biostudies-literature

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Antibody Responses to Influenza A/H1N1pdm09 Virus After Pandemic and Seasonal Influenza Vaccination in Healthcare Workers: A 5-Year Follow-up Study.

Trieu Mai-Chi MC Jul-Larsen Åsne Å Sævik Marianne M Madsen Anders A Nøstbakken Jane Kristin JK Zhou Fan F Skrede Steinar S Cox Rebecca Jane RJ

Clinical infectious diseases : an official publication of the Infectious Diseases Society of America 20190101 3

<h4>Background</h4>The 2009 influenza pandemic was caused by the A/H1N1pdm09 virus, which was subsequently included in the seasonal vaccine, up to 2016/2017, as the A/H1N1 strain. This provided a unique opportunity to investigate the antibody response to H1N1pdm09 over time.<h4>Methods</h4>Healthcare workers (HCWs) were immunized with the AS03-adjuvanted H1N1pdm09 vaccine in 2009 (N = 250), and subsequently vaccinated with seasonal vaccines containing H1N1pdm09 for 4 seasons (repeated group), <4 ...[more]

PMID: 29893797

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Project description:BackgroundSeasonal influenza is a highly contagious vaccine-preventable disease that may cause high morbidity and mortality in susceptible populations. Healthcare workers are a priority group for seasonal influenza vaccination to protect them from contracting influenza and prevent nosocomial transmission to patients. This study aimed to evaluate knowledge, attitudes, and practices (KAP) of seasonal influenza vaccination among healthcare workers in Honduras.MethodFrom August 24 to October 21, 2018, we conducted a cross-sectional KAP survey regarding seasonal influenza vaccination to a random sample of healthcare workers who attended patients in hospitals of the Ministry of Health of Honduras (SESAL) and Honduran Social Security Institute (IHSS). We reported frequency distributions of demographics, vaccination KAP, sources of information, and reasons for non-vaccination. We used principal components factor analysis to create knowledge and attitude scores. We used linear regression to analyze associations between demographics and sources of information about the influenza vaccine, and knowledge and attitude scores. We used logistic regression to analyze associations between demographics, sources of information, knowledge scores, and attitude scores, and influenza vaccination.ResultWe surveyed 947 healthcare workers who attended patients in 13 SESAL hospitals and two IHSS hospitals. Only 4.6% of participants knew the seasonal influenza vaccine was composed of inactivated viruses, 94.7% believed vaccination causes flu-like symptoms, and 52.0% were vaccinated for influenza in 2018. Knowledge scores were lower for nursing assistants and other healthcare professionals compared to doctors, and higher for healthcare workers who attended a healthcare facility training (P-values≤0.030). Attitude scores were higher for healthcare workers who attended ≥11 patients per day having ≤10 patients per day as reference, self-reported influenza vaccination in previous year, and cited trainings and informal information at the healthcare facility as sources of information for influenza vaccination (P-values≤0.030). Factors associated with self-reported vaccination were self-reported influenza vaccination in previous year (aOR: 7.61; 95% CI: 5.24-11.04), attitude score (aOR: 1.14; 95% CI: 1.07-1.21), and worked in a SESAL hospital (aOR: 1.73; 95% CI: 1.12-2.68) having IHSS as reference.ConclusionAlthough influenza vaccination is required by law in Honduras and available for free in public health centers, coverage of healthcare workers in 2018 was half that reported in 2017. Lower coverage may be attributed to misconceptions of vaccination side effects.

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:To analyze absenteeism among healthcare workers (HCWs) at a large Italian hospital and to estimate the increase in absenteeism that occurred during seasonal flu periods.Retrospective observational study.The absenteeism data were divided into three "epidemic periods," starting at week 42 of one year and terminating at week 17 of the following year (2010-2011, 2011-2012, 2012-2013), and three "non-epidemic periods," defined as week 18 to week 41 and used as baseline data. The excess of the absenteeism occurring among HCWs during periods of epidemic influenza in comparison with baseline was estimated. All data, obtained from Hospital's databases, were collected for each of the following six job categories: medical doctors, technical executives (i.e., pharmacists), nurses and allied health professionals (i.e., radiographers), other executives (i.e., engineers), nonmedical support staff, and administrative staff. The HCWs were classified by: in and no-contact; vaccinated and unvaccinated.5,544, 5,369, and 5,291 workers in three years were studied. The average duration of absenteeism during the epidemic periods increased among all employees by +2.07 days/person (from 2.99 to 5.06), and the relative increase ranged from 64-94% among the different job categories. Workers not in contact with patients experienced a slightly greater increase in absenteeism (+2.28 days/person, from 2.73 to 5.01) than did employees in contact with patients (+2.04, from 3.04 to 5.08). The vaccination rate among HCWs was below 3%, however the higher excess of absenteeism rate among unvaccinated in comparison with vaccinated workers was observed during the epidemic periods (2.09 vs 1.45 days/person).The influenza-related absenteeism during epidemic periods was quantified as totaling more than 11,000 days/year at the Italian hospital studied. This result confirms the economic impact of sick leave on healthcare systems and stresses on the necessity of encouraging HCWs to be immunized against influenza.

Dataset Information

Antibody Responses to Influenza A/H1N1pdm09 Virus After Pandemic and Seasonal Influenza Vaccination in Healthcare Workers: A 5-Year Follow-up Study.

Publications

Antibody Responses to Influenza A/H1N1pdm09 Virus After Pandemic and Seasonal Influenza Vaccination in Healthcare Workers: A 5-Year Follow-up Study.

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