Comparison of the epidemiology of laboratory-confirmed influenza A and influenza B cases in Manitoba, Canada

Hinds, Aynslie; Bozat-Emre, Songul; Caeseele, Paul Van; Mahmud, Salaheddin M.

doi:10.1186/s12889-015-1351-z

Cited by 14 publications

(11 citation statements)

References 40 publications

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“…However, the patterns observed are in line with previous studies15222324, which reported different severity of influenza A (H1N1pdm) or influenza B between Europe and North America. In our study, we considered both 2,000 and 500 confirmations as thresholds.…”

Section: Discussionsupporting

confidence: 92%

Spatio-temporal patterns of proportions of influenza B cases

Chiu

Lin

et al. 2017

Sci Rep

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We studied the spatio-temporal patterns of the proportions of influenza B cases out of all typed cases, with data from 139 countries and regions downloaded from the FluNet compiled by the World Health Organization, from January 2006 to October 2015. We restricted our analysis to 34 countries that reported more than 2,000 confirmations for each of types A and B over the study period. Globally, we found that Pearson’s correlation is greater than 0.6 between effective distance from Mexico and the proportions of influenza B cases among the countries during the post-pandemic era (i.e. Week 1, 2010 to Week 40, 2015). Locally, in the United States, the proportions of influenza B cases in the pre-pandemic period (2003–2008) negatively correlated with that in the post-pandemic era (2010–2015) at the regional level. Our study limitations are the country-level variations in both surveillance methods and testing policies. The proportions of influenza B cases displayed wide variations over the study period. Our findings suggest that the 2009 influenza pandemic has an evident impact on the relative burden of the two influenza types. Future studies should examine whether there are other additional factors. This study has potential implications in prioritizing public health control measures.

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Section: Discussionsupporting

confidence: 92%

Spatio-temporal patterns of proportions of influenza B cases

Chiu

Lin

et al. 2017

Sci Rep

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“…In previous studies comparing demographic attributes of patients with influenza A and B, a higher age for patients with influenza A was described although this may vary according to influenza A strains. Patients with H3N2 were shown to be older than influenza B patients while patients with H1N1 tended to be younger than patients with influenza B [21][22][23]. A French study by Chagvardieff et al analyzed patients presenting at an emergency department and similarly to the present results influenza B patients were significantly older [24].…”

Section: Discussionsupporting

confidence: 76%

“…Unfortunately, no information was available about influenza subtypes in the current population; however, during the season concerned influenza A/H1N1 and influenza B/Yamagata were the dominant subtypes in Austria [25]. It has been shown that patients with influenza A suffered more often from chronic diseases, such as asthma, chronic obstructive pulmonary disease, diabetes and cardiovascular disorders [22,27]. Furthermore, patients with influenza A were more likely to be smokers.…”

Section: Discussionmentioning

confidence: 99%

Is there a clinical difference between influenza A and B virus infections in hospitalized patients?

Karolyi

Pawelka

Daller

et al. 2019

Wien Klin Wochenschr

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Purpose The clinical presentation, complications and mortality in molecularly confirmed influenza A and B infections were analyzed. Methods This retrospective observational single-centre study included all influenza positive patients older than 18 years who were hospitalized and treated at the flu isolation ward during 2017/2018. The diagnosis was based on point-of-care tests with the Alere TM .Results Of the 396 patients tested positive for influenza, 24.2% had influenza A and 75.8% influenza B. Influenza A patients were younger (median age 67.5 years vs. 77 years, p < 0.001), were more often smokers (27.7% vs. 16.8%, p = 0.021), had chronic pulmonary diseases more frequently (39.6% vs. 26.3%, p = 0.013), presented with a higher body temperature (38.6°C vs. 38.3°C, p = 0.004), leucocyte count (8 G/L vs. 6.8 G/L, p = 0.002), C-reactive protein (CRP) level (41 mg/l vs. 23 mg/l, p < 0.001) and had dyspnea more often (41.7% vs. 28%, p = 0.012). Influenza B patients had an underlying chronic kidney disease in 37% vs. 18.8% (p < 0.001) and presented with vomiting on admission more frequently (21.7% vs. 11.5%, p = 0.027). Influenza A patients were admitted for 8 days vs. 7 days (p = 0.023). There were no differences in the rate of complications; however, 22 (5.6%) patients died during the hospital stay. The in-hospital mortality was higher in influenza A patients (8.3% vs 4.7%, p = 0.172). Conclusion Some differences were found between influenza A and B virus infections but symptoms were overlapping, which necessitates polymerase chain reaction point-of-care testing for accurate diagnosis. Influenza A was a more severe disease than influenza B during the period 2017/2018.

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“…Following duplicate removal (N = 946) and the screening of titles and abstracts (N = 5787), a total of 43 records were deemed to be worthy of further evaluation and the corresponding full texts were assessed. Of these, 16 papers met all inclusion criteria and were included. In the study by Caini et al only 12 of 26 study locations had a sufficient number (≥100) of isolates among the elderly.…”

Section: Resultsmentioning

confidence: 99%

Heterogeneous estimates of influenza virus types A and B in the elderly: Results of a meta‐regression analysis

Panatto

Signori

Lai

et al. 2018

Influenza Resp Viruses

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Influenza has many age‐dependent characteristics. A previous systematic review of randomized controlled trials showed that the detection rate of influenza B was higher in children than in non‐elderly adults. However, no comprehensive reviews have targeted the elderly, who carry the main burden of disease. We aimed to quantify the relative detection rates of virus types A and B among the elderly, to identify factors affecting these proportions, and to compare type distribution among seniors and younger age‐classes. A comprehensive literature search was conducted to identify multiseason studies reporting A and B virus type distributions in the elderly. A random‐effects meta‐analysis was planned to quantify the prevalence of type B among elderly subjects with laboratory‐confirmed influenza. Meta‐regression was then applied to explain the sources of heterogeneity. Across 27 estimates identified, the type B detection rate among seniors varied from 5% to 37%. Meta‐analysis was not feasible owing to high heterogeneity (I 2 = 98.5%). Meta‐regression analysis showed that study characteristics, such as number of seasons included, hemisphere, and setting, could have contributed to the heterogeneity observed. The final adjusted model showed that studies that included both outpatients and inpatients reported a significantly (P = .024) lower proportion than those involving outpatients only. The detection rate of type B among the elderly was generally lower than in children/adolescents, but not non‐elderly adults. Influenza virus type B has a relatively low detection rate in older adults, especially in settings covering both inpatients and outpatients. Public health implications are discussed.

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Comparison of the epidemiology of laboratory-confirmed influenza A and influenza B cases in Manitoba, Canada

Cited by 14 publications

References 40 publications

Spatio-temporal patterns of proportions of influenza B cases

Spatio-temporal patterns of proportions of influenza B cases

Is there a clinical difference between influenza A and B virus infections in hospitalized patients?

Heterogeneous estimates of influenza virus types A and B in the elderly: Results of a meta‐regression analysis

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