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Clinical Characteristics Are Similar across Type A and B Influenza Virus Infections.

Mosnier A, Caini S, Daviaud I, Nauleau E, Bui TT, Debost E, Bedouret B, Agius G, van der Werf S, Lina B, Cohen JM, GROG netwo - PLoS ONE (2015)

Bottom Line: There were minor differences in the distribution of signs and symptoms across influenza virus types and subtypes/lineages.Compared to patients aged 0-4 years, those aged 5-14 years were more likely to have been infected with type B viruses (OR 2.15, 95% CI 1.87-2.47) while those aged 15-64 years were less likely (OR 0.83, 95% CI 0.73-0.96).Despite differences in age distribution, the clinical illness produced by the different influenza virus types and subtypes is indistinguishable among patients that consult a general practitioner for acute respiratory infections.

View Article: PubMed Central - PubMed

Affiliation: Open Rome (Organize and Promote Epidemiological Network), Paris, France.

ABSTRACT

Background: Studies that aimed at comparing the clinical presentation of influenza patients across virus types and subtypes/lineages found divergent results, but this was never investigated using data collected over several years in a countrywide, primary care practitioners-based influenza surveillance system.

Methods: The IBVD (Influenza B in Vircases Database) study collected information on signs and symptoms at disease onset from laboratory-confirmed influenza patients of any age who consulted a sentinel practitioner in France. We compared the clinical presentation of influenza patients across age groups (0-4, 5-14, 15-64 and 65+ years), virus types (A, B) and subtypes/lineages (A(H3N2), pandemic A(H1N1), B Victoria, B Yamagata).

Results: Overall, 14,423 influenza cases (23.9% of which were influenza B) were included between 2003-2004 and 2012-2013. Influenza A and B accounted for over 50% of total influenza cases during eight and two seasons, respectively. There were minor differences in the distribution of signs and symptoms across influenza virus types and subtypes/lineages. Compared to patients aged 0-4 years, those aged 5-14 years were more likely to have been infected with type B viruses (OR 2.15, 95% CI 1.87-2.47) while those aged 15-64 years were less likely (OR 0.83, 95% CI 0.73-0.96). Males and influenza patients diagnosed during the epidemic period were less likely to be infected with type B viruses.

Conclusions: Despite differences in age distribution, the clinical illness produced by the different influenza virus types and subtypes is indistinguishable among patients that consult a general practitioner for acute respiratory infections.

No MeSH data available.


Related in: MedlinePlus

Age distribution of influenza cases by virus type and subtype.The IBVD (Influenza B in Vircases database) study, France, 2003–2004 to 2012–2013. The age distribution of H3N2 cases is shown in red, B cases in grey and H1pdm09 in blue.
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pone.0136186.g002: Age distribution of influenza cases by virus type and subtype.The IBVD (Influenza B in Vircases database) study, France, 2003–2004 to 2012–2013. The age distribution of H3N2 cases is shown in red, B cases in grey and H1pdm09 in blue.

Mentions: The age distribution of patients infected with A(H3N2), A(H1N1)pdm09 and influenza B viruses is shown in Fig 2. The proportion of cases aged 0–14 or 15+ years was 49.2% and 50.8% for A(H3N2), 59.7% and 40.3% for A(H1N1)pdm09, and 62.7% and 37.3% for type B viruses. In particular, the Kolmogorov-Smirnov test revealed that the age distributions of patients infected with the different influenza viruses were significantly different (p<0.01). Both the mean and the median age of influenza A(H3N2) patients (21.6 and 15 years, respectively) were significantly different from B (18.2 and 10 years, p<0.01 for both comparisons) and A(H1N1)pdm09 (17.1 and 11 years, p<0.01 for both comparisons) influenza patients.


Clinical Characteristics Are Similar across Type A and B Influenza Virus Infections.

Mosnier A, Caini S, Daviaud I, Nauleau E, Bui TT, Debost E, Bedouret B, Agius G, van der Werf S, Lina B, Cohen JM, GROG netwo - PLoS ONE (2015)

Age distribution of influenza cases by virus type and subtype.The IBVD (Influenza B in Vircases database) study, France, 2003–2004 to 2012–2013. The age distribution of H3N2 cases is shown in red, B cases in grey and H1pdm09 in blue.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4556513&req=5

pone.0136186.g002: Age distribution of influenza cases by virus type and subtype.The IBVD (Influenza B in Vircases database) study, France, 2003–2004 to 2012–2013. The age distribution of H3N2 cases is shown in red, B cases in grey and H1pdm09 in blue.
Mentions: The age distribution of patients infected with A(H3N2), A(H1N1)pdm09 and influenza B viruses is shown in Fig 2. The proportion of cases aged 0–14 or 15+ years was 49.2% and 50.8% for A(H3N2), 59.7% and 40.3% for A(H1N1)pdm09, and 62.7% and 37.3% for type B viruses. In particular, the Kolmogorov-Smirnov test revealed that the age distributions of patients infected with the different influenza viruses were significantly different (p<0.01). Both the mean and the median age of influenza A(H3N2) patients (21.6 and 15 years, respectively) were significantly different from B (18.2 and 10 years, p<0.01 for both comparisons) and A(H1N1)pdm09 (17.1 and 11 years, p<0.01 for both comparisons) influenza patients.

Bottom Line: There were minor differences in the distribution of signs and symptoms across influenza virus types and subtypes/lineages.Compared to patients aged 0-4 years, those aged 5-14 years were more likely to have been infected with type B viruses (OR 2.15, 95% CI 1.87-2.47) while those aged 15-64 years were less likely (OR 0.83, 95% CI 0.73-0.96).Despite differences in age distribution, the clinical illness produced by the different influenza virus types and subtypes is indistinguishable among patients that consult a general practitioner for acute respiratory infections.

View Article: PubMed Central - PubMed

Affiliation: Open Rome (Organize and Promote Epidemiological Network), Paris, France.

ABSTRACT

Background: Studies that aimed at comparing the clinical presentation of influenza patients across virus types and subtypes/lineages found divergent results, but this was never investigated using data collected over several years in a countrywide, primary care practitioners-based influenza surveillance system.

Methods: The IBVD (Influenza B in Vircases Database) study collected information on signs and symptoms at disease onset from laboratory-confirmed influenza patients of any age who consulted a sentinel practitioner in France. We compared the clinical presentation of influenza patients across age groups (0-4, 5-14, 15-64 and 65+ years), virus types (A, B) and subtypes/lineages (A(H3N2), pandemic A(H1N1), B Victoria, B Yamagata).

Results: Overall, 14,423 influenza cases (23.9% of which were influenza B) were included between 2003-2004 and 2012-2013. Influenza A and B accounted for over 50% of total influenza cases during eight and two seasons, respectively. There were minor differences in the distribution of signs and symptoms across influenza virus types and subtypes/lineages. Compared to patients aged 0-4 years, those aged 5-14 years were more likely to have been infected with type B viruses (OR 2.15, 95% CI 1.87-2.47) while those aged 15-64 years were less likely (OR 0.83, 95% CI 0.73-0.96). Males and influenza patients diagnosed during the epidemic period were less likely to be infected with type B viruses.

Conclusions: Despite differences in age distribution, the clinical illness produced by the different influenza virus types and subtypes is indistinguishable among patients that consult a general practitioner for acute respiratory infections.

No MeSH data available.


Related in: MedlinePlus