No Association between 2008–09 Influenza Vaccine and Influenza A(H1N1)pdm09 Virus Infection, Manitoba, Canada, 2009

Mahmud, Salaheddin M.; Caeseele, Paul Van; Hammond, Gregory; Kurbis, Carol; Hilderman, Tim; Elliott, Lawrence

doi:10.3201/eid1805.111596

Cited by 19 publications

(19 citation statements)

References 35 publications

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“…inpatient/outpatient, long-term care, n=5 [21, 22, 58, 91, 95]), interval between disease onset and swab (linear term or categorised, n=12), previous vaccination (e.g. seasonal & monovalent or multiple seasonal, n=14), receipt of the pneumococcal vaccine (n=2 [20, 72]), antiviral treatment (n=1 [56]), race/ethnicity (n=8 [19, 42, 47, 97, 87–90]), insurance status (n=4 [29, 37, 81, 90]), socioeconomic status (n=5 [42, 53, 56, 57, 91]), number of children in the household (n=1 [20]), whether or not the illness was medical (n=1 [89]), overseas travel (n=1 [42]), enrolment outside active recruitment (n=1 [31]), and preterm birth (n=2 [19, 47]). Only one study explored any interactions, namely the product of vaccination history and military camp [40].…”

Section: Resultsmentioning

confidence: 99%

Potential of the test-negative design for measuring influenza vaccine effectiveness: a systematic review

Sullivan¹,

Feng²,

Cowling³

2014

Expert Review of Vaccines

163

146

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SUMMARY Background The test-negative design is a variant of the case control study being increasingly used to study influenza vaccine effectiveness. In these studies, patients with influenza-like illness are tested for influenza. Vaccine coverage is compared between those testing positive versus those testing negative to estimate vaccine effectiveness. Objectives We reviewed features in the design, analysis and reporting of 85 published test-negative studies. Data sources Studies were identified from PubMed, reference lists and email updates. Study eligibility All studies using the test-negative design reporting end-of-season estimates were included. Study appraisal Design features that may affect the validity and comparability of reported estimates were reviewed, including setting, study period, source population, case definition, exposure and outcome ascertainment and statistical model. Results There was considerable variation in the analytic approach, with 68 unique statistical models identified among the studies. Conclusion Harmonisation of analytic approaches may improve the potential for pooling vaccine effectiveness estimates.

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Section: Resultsmentioning

confidence: 99%

Potential of the test-negative design for measuring influenza vaccine effectiveness: a systematic review

Sullivan¹,

Feng²,

Cowling³

2014

Expert Review of Vaccines

163

146

View full text Add to dashboard Cite

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“…These studies suggested a significant protective effect of 35%–73% against infection, particularly severe forms of the disease during the early pandemic phase [20], [21]. By contrast, other epidemiological studies have found no association [24], [36], [37], [38], [39], [40], [41], [42] or a mild benefit [43], [44] against infection or hospitalization with laboratory-confirmed pandemic A/H1N1 from the 2008–2009 seasonal influenza vaccine. However, these studies did not quantify the effect of seasonal influenza vaccine against death associated with pandemic A/H1N1 infection.…”

Section: Discussionmentioning

confidence: 98%

Epidemiological Characteristics and Underlying Risk Factors for Mortality during the Autumn 2009 Pandemic Wave in Mexico

et al. 2012

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BackgroundElucidating the role of the underlying risk factors for severe outcomes of the 2009 A/H1N1 influenza pandemic could be crucial to define priority risk groups in resource-limited settings in future pandemics.MethodsWe use individual-level clinical data on a large series of ARI (acute respiratory infection) hospitalizations from a prospective surveillance system of the Mexican Social Security medical system to analyze clinical features at presentation, admission delays, selected comorbidities and receipt of seasonal vaccine on the risk of A/H1N1-related death. We considered ARI hospitalizations and inpatient-deaths, and recorded demographic, geographic, and medical information on individual patients during August-December, 2009.ResultsSeasonal influenza vaccination was associated with a reduced risk of death among A/H1N1 inpatients (OR = 0.43 (95% CI: 0.25, 0.74)) after adjustment for age, gender, geography, antiviral treatment, admission delays, comorbidities and medical conditions. However, this result should be interpreted with caution as it could have been affected by factors not directly measured in our study. Moreover, the effect of antiviral treatment against A/H1N1 inpatient death did not reach statistical significance (OR = 0.56 (95% CI: 0.29, 1.10)) probably because only 8.9% of A/H1N1 inpatients received antiviral treatment. Moreover, diabetes (OR = 1.6) and immune suppression (OR = 2.3) were statistically significant risk factors for death whereas asthmatic persons (OR = 0.3) or pregnant women (OR = 0.4) experienced a reduced fatality rate among A/H1N1 inpatients. We also observed an increased risk of death among A/H1N1 inpatients with admission delays >2 days after symptom onset (OR = 2.7). Similar associations were also observed for A/H1N1-negative inpatients.ConclusionsGeographical variation in identified medical risk factors including prevalence of diabetes and immune suppression may in part explain between-country differences in pandemic mortality burden. Furthermore, access to care including hospitalization without delay and antiviral treatment and are also important factors, as well as vaccination coverage with the 2008–09 trivalent inactivated influenza vaccine.

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“…For the non-randomized studies, based on the NOS scoring system, 3 of the cohort studies had moderate risk, whereas one study 22 had high risk of bias. For the case-control studies, 9 had low-risk bias 8,9,10,14,15,24,28,29,31 , while the other 11 had moderate-risk bias [5][6][7]13,15,[25][26][27]30,32 . The details of the quality assessment are shown in the Supplemental Tables 5-8.…”

Section: General Informationmentioning

confidence: 99%

“…S2 and S3). Case-control study A slight risk reduction was observed in 16 casecontrol studies [5][6][7]9,10,[13][14][15]25,27,[29][30][31][32] that reported laboratory-confirmed cases (OR: 0.80; 95% CI: 0.61, 1.05; P D 0.11). However, a significant heterogeneity was also found across these studies (I 2 D 93%; P < 0.00001) (Fig.…”

Section: Cohort Studymentioning

confidence: 99%

“…6 In this review, we divided the study by Skowronski et al 15 into one cohort study and 3 case-control studies (Quebec household transmission study as Skowronski-a, national sentinel monitoring system as Skowronski-b, Quebec population case-control study as Skowronski-c, Ontario test-negative case-control study as Skowronskid). This systematic review included 4 RCTs, 11,12,18,19 4 cohort studies, 15,16,22,23 and 20 case-control studies [5][6][7][8][9][10][13][14][15][24][25][26][27][28][29][30][31][32] . In addition, 2 surveillance reports and one outbreak investigation were included.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Partial protection against 2009 pandemic influenza A (H1N1) of seasonal influenza vaccination and related regional factors: Updated systematic review and meta-analyses

Chen

Zhang

et al. 2015

Human Vaccines & Immunotherapeutics

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No Association between 2008–09 Influenza Vaccine and Influenza A(H1N1)pdm09 Virus Infection, Manitoba, Canada, 2009

Abstract: Receipt of seasonal inactivated trivalent vaccine neither increased nor decreased the risk for pandemic influenza virus infection.

Cited by 19 publications

References 35 publications

Potential of the test-negative design for measuring influenza vaccine effectiveness: a systematic review

Potential of the test-negative design for measuring influenza vaccine effectiveness: a systematic review

Epidemiological Characteristics and Underlying Risk Factors for Mortality during the Autumn 2009 Pandemic Wave in Mexico

Partial protection against 2009 pandemic influenza A (H1N1) of seasonal influenza vaccination and related regional factors: Updated systematic review and meta-analyses

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