16 results on '"repeat vaccination"'
Search Results
2. Immune History and Influenza Vaccine Effectiveness.
- Author
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Lewnard, Joseph and Cobey, Sarah
- Subjects
imprinting ,original antigenic sin ,repeat vaccination ,seasonal influenza vaccine ,test-negative design ,universal influenza vaccine ,vaccine effectiveness - Abstract
The imperfect effectiveness of seasonal influenza vaccines is often blamed on antigenic mismatch, but even when the match appears good, effectiveness can be surprisingly low. Seasonal influenza vaccines also stand out for their variable effectiveness by age group from year to year and by recent vaccination status. These patterns suggest a role for immune history in influenza vaccine effectiveness, but inference is complicated by uncertainty about the contributions of bias to the estimates themselves. In this review, we describe unexpected patterns in the effectiveness of seasonal influenza vaccination and explain how these patterns might arise as consequences of study design, the dynamics of immune memory, or both. Resolving this uncertainty could lead to improvements in vaccination strategy, including the use of universal vaccines in experienced populations, and the evaluation of vaccine efficacy against influenza and other antigenically variable pathogens.
- Published
- 2018
3. Is annual vaccination best? A modelling study of influenza vaccination strategies in children.
- Author
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Ainslie, Kylie E.C. and Riley, Steven
- Subjects
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VACCINATION of children , *INFLUENZA , *INFLUENZA vaccines , *VACCINATION , *VACCINATION coverage , *COHORT analysis , *FLOOD damage - Abstract
Annual vaccination of children against influenza is a key component of vaccination programs in many countries. However, past infection and vaccination may affect an individual's susceptibility to infection. Little research has evaluated whether annual vaccination is the best strategy. Using the United Kingdom as our motivating example, we developed a framework to assess the impact of different childhood vaccination strategies, specifically annual and biennial (every other year), on attack rate and expected number of infections. We present a multi-annual, individual-based, stochastic, force of infection model that accounts for individual exposure histories and disease/vaccine dynamics influencing susceptibility. We simulate birth cohorts that experience yearly influenza epidemics and follow them until age 18 to determine attack rates and the number of infections during childhood. We perform simulations under baseline conditions, with an assumed vaccination coverage of 44%, to compare annual vaccination to no and biennial vaccination. We relax our baseline assumptions to explore how our model assumptions impact vaccination program performance. At baseline, we observed less than half the number of infections between the ages 2 and 10 under annual vaccination in children who had been vaccinated at least half the time compared to no vaccination. When averaged over all ages 0–18, the number of infections under annual vaccination was 2.07 (2.06, 2.08) compared to 2.63 (2.62, 2.64) under no vaccination, and 2.38 (2.37, 2.40) under biennial vaccination. When we introduced a penalty for repeated exposures, we observed a decrease in the difference in infections between the vaccination strategies. Specifically, the difference in childhood infections under biennial compared to annual vaccination decreased from 0.31 to 0.04 as exposure penalty increased. Our results indicate that while annual vaccination averts more childhood infections than biennial vaccination, this difference is small. Our work confirms the value of annual vaccination in children, even with modest vaccination coverage, but also shows that similar benefits of vaccination may be obtained by implementing a biennial vaccination program. Many countries include annual vaccination of children against influenza in their vaccination programs. In the United Kingdom (UK), annual vaccination of children aged of 2 to 10 against influenza is recommended. However, little research has evaluated whether annual vaccination is the best strategy, while accounting for how past infection and vaccination may affect an individual's susceptibility to infection in the current influenza season. Prior work has suggested that there may be a negative effect of repeated vaccination. In this work we developed a stochastic, individual-based model to assess the impact of repeated vaccination strategies on childhood infections. Specifically, we first compare annual vaccination to no vaccination and then annual vaccination to biennial (every other year) vaccination. We use the UK as our motivating example. We found that an annual vaccination strategy resulted in the fewest childhood infections, followed by biennial vaccination. The difference in number of childhood infections between the different vaccination strategies decreased when we introduced a penalty for repeated exposures. Our work confirms the value of annual vaccination in children, but also shows that similar benefits of vaccination can be obtained by implementing a biennial vaccination program, particularly when there is a negative effect of repeated vaccinations. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
4. Effects of Prior Season Vaccination on Current Season Vaccine Effectiveness in the United States Flu Vaccine Effectiveness Network, 2012–2013 Through 2017–2018.
- Author
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Kim, Sara S, Flannery, Brendan, Foppa, Ivo M, Chung, Jessie R, Nowalk, Mary Patricia, Zimmerman, Richard K, Gaglani, Manjusha, Monto, Arnold S, Martin, Emily T, Belongia, Edward A, McLean, Huong Q, Jackson, Michael L, Jackson, Lisa A, and Patel, Manish
- Subjects
- *
INFLUENZA prevention , *INFLUENZA vaccines , *IMMUNIZATION , *CONFIDENCE intervals , *AGE distribution , *TIME , *DESCRIPTIVE statistics , *LOGISTIC regression analysis - Abstract
Background We compared effects of prior vaccination and added or lost protection from current season vaccination among those previously vaccinated. Methods Our analysis included data from the US Flu Vaccine Effectiveness Network among participants ≥9 years old with acute respiratory illness from 2012–2013 through 2017–2018. Vaccine protection was estimated using multivariate logistic regression with an interaction term for effect of prior season vaccination on current season vaccine effectiveness. Models were adjusted for age, calendar time, high-risk status, site, and season for combined estimates. We estimated protection by combinations of current and prior vaccination compared to unvaccinated in both seasons or current vaccination among prior vaccinated. Results A total of 31 819 participants were included. Vaccine protection against any influenza averaged 42% (95% confidence interval [CI], 38%–47%) among those vaccinated only the current season, 37% (95% CI, 33–40) among those vaccinated both seasons, and 26% (95% CI, 18%–32%) among those vaccinated only the prior season, compared with participants vaccinated neither season. Current season vaccination reduced the odds of any influenza among patients unvaccinated the prior season by 42% (95% CI, 37%–46%), including 57%, 27%, and 55% against A(H1N1), A(H3N2), and influenza B, respectively. Among participants vaccinated the prior season, current season vaccination further reduced the odds of any influenza by 15% (95% CI, 7%–23%), including 29% against A(H1N1) and 26% against B viruses, but not against A(H3N2). Conclusions Our findings support Advisory Committee on Immunization Practices recommendations for annual influenza vaccination. Benefits of current season vaccination varied among participants with and without prior season vaccination, by virus type/subtype and season. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
5. Longitudinal Assessment of Immune Responses to Repeated Annual Influenza Vaccination in a Human Cohort of Adults and Teenagers
- Author
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Meng-Hsuan Sung, Ye Shen, Andreas Handel, Justin Bahl, and Ted M. Ross
- Subjects
influenza vaccine ,hemagglutination inhibition assay ,composite score ,repeat vaccination ,immune responses ,Immunologic diseases. Allergy ,RC581-607 - Abstract
Background: The overall performance of a multiple component vaccine assessed by the vaccine-elicited immune responses across various strains in a repeated vaccination setting has not been well-studied, and the comparison between adults and teenagers is yet to be made.Methods: A human cohort study was conducted at the University of Georgia, with 140 subjects (86 adults and 54 teenagers) repeatedly vaccinated in the 2017/2018 and 2018/2019 influenza seasons. Host information was prospectively collected, and serum samples were collected before and after vaccination in each season. The association between host factors and repeated measures of hemagglutination inhibition (HAI) composite scores was assessed by generalized linear models with generalized estimating equations.Results: The mean HAI composite scores for the entire sample (t = 4.26, df = 139, p < 0.001) and the teenager group (t = 6.44, df = 53, p < 0.001) declined in the second season, while the changes in the adults were not statistically significant (t = −1.14, df = 85, p = 0.26). A mixture pattern of changes in both directions was observed in the adults when stratified by prior vaccination. In addition, the regression analysis suggested an interactive effect of age and BMI on the HAI composite scores in the overall population (beta = 0.005; 95% CI, 0.0008–0.01) and the adults (beta = 0.005; 95% CI, 0.0005–0.01).Conclusions: Our study found distinct vaccine-elicited immune responses between adults and teenagers when both were repeatedly vaccinated in consecutive years. An interactive effect of age and BMI on the HAI composite scores were identified in the overall population and the adults.
- Published
- 2021
- Full Text
- View/download PDF
6. Longitudinal Assessment of Immune Responses to Repeated Annual Influenza Vaccination in a Human Cohort of Adults and Teenagers.
- Author
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Sung, Meng-Hsuan, Shen, Ye, Handel, Andreas, Bahl, Justin, and Ross, Ted M.
- Subjects
INFLUENZA vaccines ,IMMUNE response ,GENERALIZED estimating equations ,TEENAGERS ,ADULTS - Abstract
Background: The overall performance of a multiple component vaccine assessed by the vaccine-elicited immune responses across various strains in a repeated vaccination setting has not been well-studied, and the comparison between adults and teenagers is yet to be made. Methods: A human cohort study was conducted at the University of Georgia, with 140 subjects (86 adults and 54 teenagers) repeatedly vaccinated in the 2017/2018 and 2018/2019 influenza seasons. Host information was prospectively collected, and serum samples were collected before and after vaccination in each season. The association between host factors and repeated measures of hemagglutination inhibition (HAI) composite scores was assessed by generalized linear models with generalized estimating equations. Results: The mean HAI composite scores for the entire sample (t = 4.26, df = 139, p < 0.001) and the teenager group (t = 6.44, df = 53, p < 0.001) declined in the second season, while the changes in the adults were not statistically significant (t = −1.14, df = 85, p = 0.26). A mixture pattern of changes in both directions was observed in the adults when stratified by prior vaccination. In addition, the regression analysis suggested an interactive effect of age and BMI on the HAI composite scores in the overall population (beta = 0.005; 95% CI, 0.0008–0.01) and the adults (beta = 0.005; 95% CI, 0.0005–0.01). Conclusions: Our study found distinct vaccine-elicited immune responses between adults and teenagers when both were repeatedly vaccinated in consecutive years. An interactive effect of age and BMI on the HAI composite scores were identified in the overall population and the adults. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
7. Vaccine Effectiveness Against Lineage-matched and -mismatched Influenza B Viruses Across 8 Seasons in Canada, 2010–2011 to 2017–2018.
- Author
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Skowronski, Danuta M, Jassem, Agatha, Rose, Caren, Krajden, Mel, Petric, Martin, Bastien, Nathalie, Li, Yan, Chambers, Catharine, Sabaiduc, Suzana, Hickman, Rebecca, Chan, Tracy, Serres, Gaston De, Winter, Anne-Luise, Dickinson, James A, Gubbay, Jonathan B, Drews, Steven J, Fonseca, Kevin, Charest, Hugues, and Martineau, Christine
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- *
INFLUENZA vaccines , *INFLUENZA epidemiology , *INFLUENZA , *TREATMENT effectiveness , *INFLUENZA B virus , *VACCINATION , *THERAPEUTICS - Abstract
Vaccine effectiveness (VE) against influenza B was derived separately for Victoria and Yamagata lineages across 8 seasons (2010–2011 to 2017–2018) in Canada when trivalent influenza vaccine was predominantly used. VE was ≥50% regardless of lineage match to circulating viruses, except when the vaccine strain was unchanged from the prior season. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
8. Dose-Dependent Negative Effects of Prior Multiple Vaccinations Against Influenza A and Influenza B Among Schoolchildren: A Study of Kamigoto Island in Japan During the 2011–2012, 2012–2013, and 2013–2014 Influenza Seasons.
- Author
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Saito, Nobuo, Komori, Kazuhiro, Suzuki, Motoi, Kishikawa, Takayuki, Yasaka, Takahiro, and Ariyoshi, Koya
- Subjects
- *
CONFIDENCE intervals , *REPORTING of diseases , *DOSE-effect relationship in pharmacology , *HOSPITALS , *IMMUNIZATION , *INFLUENZA vaccines , *JAPANESE people , *STUDENT health , *LOGISTIC regression analysis , *INFLUENZA A virus , *TREATMENT effectiveness , *CASE-control method , *INFLUENZA B virus , *CHILDREN , *SEASONAL influenza , *DIAGNOSIS , *PREVENTION - Abstract
Background We investigated the negative effects of prior multiple vaccinations on influenza vaccine effectiveness (VE) and analyzed the association of VE with prior vaccine doses. Methods Patients aged 9–18 years presenting with influenza-like illness at a community hospital on a remote Japanese island during the 2011–2012, 2012–2013, and 2013–2014 influenza seasons were tested for influenza using a rapid diagnostic test (RDT). A test-negative, case-control study design was used to estimate the VEs of trivalent inactivated influenza vaccine. Histories of vaccination and medically attended influenza (MA-flu) A and B during 3 previous seasons were collected from registry systems. VE was calculated using multilevel mixed-effects logistic regression models adjusted for the history of RDT-confirmed MA-flu. Results During 3 influenza seasons, 1668 influenza-like illness episodes were analyzed, including 421 and 358 episodes of MA-fluA and MA-fluB, respectively. The adjusted VE (95% confidence interval) yielded significant dose-dependent attenuations by prior vaccinations against both MA-fluA (0 doses during previous 3 seasons: 96% [69%–100%], 1 dose: 48% [−7% to 74%], 2 doses: 52% [11%–74%], 3 doses: 21% [−25% to 51%]; P for trend <.05) and MA-fluB (0 doses: 66% [−5% to 89%], 1 dose: 48% [−14% to 76%], 2 doses: 34% [−33% to 67%], 3 doses: −7% [−83% to 37%]; P for trend <.05). After excluding episodes of MA-flu during prior 3 seasons, similar trends were observed. Conclusions Repeated previous vaccinations over multiple seasons had significant dose-dependent negative impacts on VE against both MA-fluA and MA-fluB. Further studies to confirm this finding are necessary. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
9. Beyond Antigenic Match: Possible Agent-Host and Immuno-epidemiological Influences on Influenza Vaccine Effectiveness During the 2015-2016 Season in Canada.
- Author
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Skowronski, Danuta M., Chambers, Catharine, Sabaiduc, Suzana, De Serres, Gaston, Winter, Anne-Luise, Dickinson, James A., Gubbay, Jonathan B., Drews, Steven J., Martineau, Christine, Charest, Hugues, Krajden, Mel, Bastien, Nathalie, Yan Li, and Li, Yan
- Subjects
- *
VACCINE effectiveness , *INFLUENZA vaccines , *SEASONAL influenza , *INFLUENZA A virus , *INFLUENZA A virus, H1N1 subtype , *INFLUENZA prevention , *INFLUENZA epidemiology , *AGE distribution , *BIOCHEMISTRY , *CLUSTER analysis (Statistics) , *COMPARATIVE studies , *BIOLOGICAL evolution , *HEMAGGLUTINATION tests , *IMMUNIZATION , *INFLUENZA , *PHENOMENOLOGY , *RESEARCH methodology , *MEDICAL cooperation , *RESEARCH , *VIRAL antigens , *EVALUATION research , *TREATMENT effectiveness , *INFLUENZA B virus , *SEQUENCE analysis - Abstract
Background: Vaccine effectiveness (VE) estimates for 2015-2016 seasonal influenza vaccine are reported from Canada's Sentinel Practitioner Surveillance Network (SPSN). This season was characterized by a delayed 2009 pandemic influenza A(H1N1) virus (A[H1N1]pdm09) epidemic and concurrent influenza B(Victoria) virus activity. Potential influences on VE beyond antigenic match are explored, including viral genomic variation, birth cohort effects, prior vaccination, and epidemic period.Methods: VE was estimated by a test-negative design comparing the adjusted odds ratio for influenza test positivity among vaccinated compared to unvaccinated participants. Vaccine-virus relatedness was assessed by gene sequencing and hemagglutination inhibition assay.Results: Analyses included 596 influenza A(H1N1)pdm09 and 305 B(Victoria) cases and 926 test-negative controls. A(H1N1)pdm09 viruses were considered antigenically related to vaccine (unchanged since 2009), despite phylogenetic clustering within emerging clade 6B.1. The adjusted VE against A(H1N1)pdm09 was 43% (95% confidence interval [CI], 25%-57%). Compared to other age groups, VE against A(H1N1)pdm09 was lower for adults born during 1957-1976 (25%; 95% CI, -16%-51%). The VE against A(H1N1)pdm09 was also lower for participants consecutively vaccinated during both the current and prior seasons (41%; 95% CI, 18%-57%) than for those vaccinated during the current season only (75%; 95% CI, 45%-88%), and the VE among participants presenting in March-April 2016 (19%; 95% CI, -15%-44%) was lower than that among those presenting during January-February 2016 (62%; 95% CI, 44%-74%). The adjusted VE for B(Victoria) viruses was 54% (95% CI, 32%-68%), despite lineage-level mismatch to B(Yamagata) vaccine. The further variation in VE as observed for A(H1N1)pdm09 was not observed for B(Victoria).Conclusions: Influenza VE findings may require consideration of other agent-host and immuno-epidemiologic influences on vaccine performance beyond antigenic match, including viral genomic variation, repeat vaccination, birth (immunological) cohort effects, and potential within-season waning of vaccine protection. [ABSTRACT FROM AUTHOR]- Published
- 2017
- Full Text
- View/download PDF
10. Serial Vaccination and the Antigenic Distance Hypothesis: Effects on Influenza Vaccine Effectiveness During A(H3N2) Epidemics in Canada, 2010-2011 to 2014-2015.
- Author
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Skowronski, Danuta M., Chambers, Catharine, De Serres, Gaston, Sabaiduc, Suzana, Winter, Anne-Luise, Dickinson, James A., Gubbay, Jonathan B., Fonseca, Kevin, Drews, Steven J., Charest, Hugues, Martineau, Christine, Krajden, Mel, Petric, Martin, Bastien, Nathalie, Yan Li, Smith, Derek J., and Li, Yan
- Subjects
- *
INFLUENZA vaccines , *VACCINE effectiveness , *INFLUENZA A virus , *NUCLEOTIDE sequencing , *BLOOD agglutination - Abstract
Background: The antigenic distance hypothesis (ADH) predicts that negative interference from prior season's influenza vaccine (v1) on the current season's vaccine (v2) protection may occur when the antigenic distance is small between v1 and v2 (v1 ≈ v2) but large between v1 and the current epidemic (e) strain (v1 ≠ e).Methods: Vaccine effectiveness (VE) against medically attended, laboratory-confirmed influenza A(H3N2) illness was estimated by test-negative design during 3 A(H3N2) epidemics (2010-2011, 2012-2013, 2014-2015) in Canada. Vaccine effectiveness was derived with covariate adjustment across v2 and/or v1 categories relative to no vaccine receipt among outpatients aged ≥9 years. Prior vaccination effects were interpreted within the ADH framework.Results: Prior vaccination effects varied significantly by season, consistent with the ADH. There was no interference by v1 in 2010-2011 when v1 ≠ v2 and v1 ≠ e, with comparable VE for v2 alone or v2 + v1: 34% (95% confidence interval [CI] = -51% to 71%) versus 34% (95% CI = -5% to 58%). Negative interference by v1 was suggested in 2012-2013 with nonsignificant reduction in VE when v1 ≈ v2 and v1 ≠ e: 49% (95% CI = -47% to 83%) versus 28% (95% CI = -12% to 54%). Negative effects of prior vaccination were pronounced and statistically significant in 2014-2015 when v1 ≡ v2 and v1 ≠ e: 65% (95% CI = 25% to 83%) versus -33% (95% CI = -78% to 1%).Conclusions: Effects of repeat influenza vaccination were consistent with the ADH and may have contributed to findings of low VE across recent A(H3N2) epidemics since 2010 in Canada. [ABSTRACT FROM AUTHOR]- Published
- 2017
- Full Text
- View/download PDF
11. Immune History and Influenza Vaccine Effectiveness
- Author
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Joseph A. Lewnard and Sarah Cobey
- Subjects
vaccine effectiveness ,repeat vaccination ,original antigenic sin ,test-negative design ,seasonal influenza vaccine ,universal influenza vaccine ,imprinting ,Medicine - Abstract
The imperfect effectiveness of seasonal influenza vaccines is often blamed on antigenic mismatch, but even when the match appears good, effectiveness can be surprisingly low. Seasonal influenza vaccines also stand out for their variable effectiveness by age group from year to year and by recent vaccination status. These patterns suggest a role for immune history in influenza vaccine effectiveness, but inference is complicated by uncertainty about the contributions of bias to the estimates themselves. In this review, we describe unexpected patterns in the effectiveness of seasonal influenza vaccination and explain how these patterns might arise as consequences of study design, the dynamics of immune memory, or both. Resolving this uncertainty could lead to improvements in vaccination strategy, including the use of universal vaccines in experienced populations, and the evaluation of vaccine efficacy against influenza and other antigenically variable pathogens.
- Published
- 2018
- Full Text
- View/download PDF
12. Untangling the Effects of Prior Vaccination on Subsequent Influenza Vaccine Effectiveness.
- Author
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Petrie, Joshua G. and Monto, Arnold S.
- Subjects
- *
INFLUENZA vaccines , *ANTIGENIC drift , *IMMUNITY , *IMMUNIZATION , *PREVENTION of communicable diseases - Abstract
The article offers the authors' view the impact of pre-vaccination on the effective successive influenza vaccination. They mention the antigenic attributes of influenza virus leading to the introduction of vaccination for inducing immunity against it. An overview of the study indicating the reduction of the vaccine's effectiveness is also presented.
- Published
- 2017
- Full Text
- View/download PDF
13. Vaccine Effectiveness Against Lineage-matched and -mismatched Influenza B Viruses Across 8 Seasons in Canada, 2010–2011 to 2017–2018
- Author
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Catharine Chambers, Danuta M. Skowronski, Yan Li, Jonathan B. Gubbay, Suzana Sabaiduc, Christine Martineau, Gaston De Serres, Hugues Charest, Tracy Chan, Anne-Luise Winter, Steven J. Drews, Kevin Fonseca, Mel Krajden, James A. Dickinson, Caren Rose, Martin Petric, Agatha N. Jassem, Rebecca Hickman, and Nathalie Bastien
- Subjects
Adult ,Male ,0301 basic medicine ,Microbiology (medical) ,Trivalent influenza vaccine ,Canada ,cross-protection ,Lineage (genetic) ,Adolescent ,Databases, Factual ,Cross Protection ,030106 microbiology ,Young Adult ,03 medical and health sciences ,Immunogenicity, Vaccine ,0302 clinical medicine ,Vaccine strain ,influenza vaccine effectiveness ,Influenza, Human ,Humans ,Medicine ,030212 general & internal medicine ,Child ,Vaccine Potency ,Aged ,Influenza B viruses ,business.industry ,Influenzavirus B ,repeat vaccination ,Infant ,Middle Aged ,influenza B virus ,Virology ,3. Good health ,Vaccination ,Infectious Diseases ,Immunization ,Influenza Vaccines ,Child, Preschool ,Epidemiological Monitoring ,Female ,Brief Reports ,Seasons ,business ,lineage - Abstract
Vaccine effectiveness (VE) against influenza B was derived separately for Victoria and Yamagata lineages across 8 seasons (2010–2011 to 2017–2018) in Canada when trivalent influenza vaccine was predominantly used. VE was ≥50% regardless of lineage match to circulating viruses, except when the vaccine strain was unchanged from the prior season.
- Published
- 2018
14. Beyond Antigenic Match: Moving Toward Greater Understanding of Influenza Vaccine Effectiveness
- Author
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Edward A. Belongia
- Subjects
0301 basic medicine ,Canada ,Influenza vaccine ,030106 microbiology ,hemagglutination inhibition ,influenza B lineage ,original antigenic sin ,Major Articles and Brief Reports ,03 medical and health sciences ,Influenza A Virus, H1N1 Subtype ,0302 clinical medicine ,Match moving ,Antigen ,Influenza, Human ,Humans ,Immunology and Allergy ,Medicine ,030212 general & internal medicine ,vaccine effectiveness ,business.industry ,birth cohort effects ,repeat vaccination ,sequencing ,Virology ,Influenza ,Infectious Diseases ,Influenza Vaccines ,Viruses ,Immunology ,Seasons ,influenza vaccine ,business ,influenza A subtype - Abstract
Vaccine effectiveness estimates for 2015–2016 seasonal influenza vaccine are reported from Canada. Findings suggest that agent-host and immuno-epidemiologic factors beyond antigenic match—including viral genomic variation, birth (immunological) cohort effects, repeat vaccination, and potential within-season waning immunity—may influence vaccine performance., Background Vaccine effectiveness (VE) estimates for 2015–2016 seasonal influenza vaccine are reported from Canada’s Sentinel Practitioner Surveillance Network (SPSN). This season was characterized by a delayed 2009 pandemic influenza A(H1N1) virus (A[H1N1]pdm09) epidemic and concurrent influenza B(Victoria) virus activity. Potential influences on VE beyond antigenic match are explored, including viral genomic variation, birth cohort effects, prior vaccination, and epidemic period. Methods VE was estimated by a test-negative design comparing the adjusted odds ratio for influenza test positivity among vaccinated compared to unvaccinated participants. Vaccine-virus relatedness was assessed by gene sequencing and hemagglutination inhibition assay. Results Analyses included 596 influenza A(H1N1)pdm09 and 305 B(Victoria) cases and 926 test-negative controls. A(H1N1)pdm09 viruses were considered antigenically related to vaccine (unchanged since 2009), despite phylogenetic clustering within emerging clade 6B.1. The adjusted VE against A(H1N1)pdm09 was 43% (95% confidence interval [CI], 25%–57%). Compared to other age groups, VE against A(H1N1)pdm09 was lower for adults born during 1957–1976 (25%; 95% CI, −16%–51%). The VE against A(H1N1)pdm09 was also lower for participants consecutively vaccinated during both the current and prior seasons (41%; 95% CI, 18%–57%) than for those vaccinated during the current season only (75%; 95% CI, 45%–88%), and the VE among participants presenting in March–April 2016 (19%; 95% CI, −15%–44%) was lower than that among those presenting during January–February 2016 (62%; 95% CI, 44%–74%). The adjusted VE for B(Victoria) viruses was 54% (95% CI, 32%–68%), despite lineage-level mismatch to B(Yamagata) vaccine. The further variation in VE as observed for A(H1N1)pdm09 was not observed for B(Victoria). Conclusions Influenza VE findings may require consideration of other agent-host and immuno-epidemiologic influences on vaccine performance beyond antigenic match, including viral genomic variation, repeat vaccination, birth (immunological) cohort effects, and potential within-season waning of vaccine protection.
- Published
- 2017
15. Immune History and Influenza Vaccine Effectiveness.
- Author
-
Lewnard, Joseph A, Lewnard, Joseph A, Cobey, Sarah, Lewnard, Joseph A, Lewnard, Joseph A, and Cobey, Sarah
- Abstract
The imperfect effectiveness of seasonal influenza vaccines is often blamed on antigenic mismatch, but even when the match appears good, effectiveness can be surprisingly low. Seasonal influenza vaccines also stand out for their variable effectiveness by age group from year to year and by recent vaccination status. These patterns suggest a role for immune history in influenza vaccine effectiveness, but inference is complicated by uncertainty about the contributions of bias to the estimates themselves. In this review, we describe unexpected patterns in the effectiveness of seasonal influenza vaccination and explain how these patterns might arise as consequences of study design, the dynamics of immune memory, or both. Resolving this uncertainty could lead to improvements in vaccination strategy, including the use of universal vaccines in experienced populations, and the evaluation of vaccine efficacy against influenza and other antigenically variable pathogens.
- Published
- 2018
16. A systematic review of the efficacy of live attenuated influenza vaccine upon revaccination of children.
- Author
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Caspard H, Heikkinen T, Belshe RB, and Ambrose CS
- Subjects
- Child, Child, Preschool, Humans, Infant, Placebos administration & dosage, Randomized Controlled Trials as Topic, Treatment Outcome, Vaccines, Attenuated administration & dosage, Vaccines, Attenuated immunology, Immunization, Secondary, Influenza Vaccines administration & dosage, Influenza Vaccines immunology
- Abstract
Four randomized, double-blind, placebo-controlled studies in 6090 children that investigated the efficacy of live attenuated influenza vaccine (LAIV) upon revaccination of children against laboratory-confirmed cases of influenza in consecutive seasons were reviewed. The efficacy in season 2 of LAIV administered over 2 consecutive seasons was 86.7% (95 % CI: 76.8%, 92.4%) against strains antigenically similar to those contained in the vaccine. The additional efficacy of LAIV administered in season 2 compared to LAIV recipients in season 1 only was 58.4% (28.3%, 75.9%). LAIV administered over 2 consecutive seasons also was more efficacious than was LAIV administered in season 2 only (relative efficacy: 53.9% [17.4%, 74.3%]). Residual efficacy of LAIV administered in season 1 only compared to placebo administered in two consecutive seasons was 56.4% (37.0%, 69.8%). This review did not find any evidence of decreasing efficacy of LAIV when administered during 2 consecutive seasons.
- Published
- 2016
- Full Text
- View/download PDF
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