tetano
Editor, Senior Moderator
Lancet Respir Med. 2015 Aug 20. pii: S2213-2600(15)00278-7. doi: 10.1016/S2213-2600(15)00278-7. [Epub ahead of print]
Incidence of medically attended influenza during pandemic and post-pandemic seasons through the Influenza Incidence Surveillance Project, 2009-13.
Fowlkes A[SUP]1[/SUP], Steffens A[SUP]1[/SUP], Temte J[SUP]2[/SUP], Lonardo SD[SUP]3[/SUP], McHugh L[SUP]4[/SUP], Martin K[SUP]5[/SUP], Rubino H[SUP]6[/SUP], Feist M[SUP]7[/SUP], Davis C[SUP]8[/SUP], Selzer C[SUP]9[/SUP], Lojo J[SUP]10[/SUP], Oni O[SUP]11[/SUP], Kurkjian K[SUP]12[/SUP], Thomas A[SUP]13[/SUP], Boulton R[SUP]14[/SUP], Bryan N[SUP]15[/SUP], Lynfield R[SUP]5[/SUP], Biggerstaff M[SUP]1[/SUP], Finelli L[SUP]1[/SUP]; Influenza Incidence Surveillance Project Working Group.
Author information
Abstract
BACKGROUND:
Since the introduction of pandemic influenza A (H1N1) to the USA in 2009, the Influenza Incidence Surveillance Project has monitored the burden of influenza in the outpatient setting through population-based surveillance.
METHODS:
From Oct 1, 2009, to July 31, 2013, outpatient clinics representing 13 health jurisdictions in the USA reported counts of influenza-like illness (fever including cough or sore throat) and all patient visits by age. During four years, staff at 104 unique clinics (range 35-64 per year) with a combined median population of 368 559 (IQR 352 595-428 286) attended 35 663 patients with influenza-like illness and collected 13 925 respiratory specimens. Clinical data and a respiratory specimen for influenza testing by RT-PCR were collected from the first ten patients presenting with influenza-like illness each week. We calculated the incidence of visits for influenza-like illness using the size of the patient population, and the incidence attributable to influenza was extrapolated from the proportion of patients with positive tests each week.
FINDINGS:
The site-median peak percentage of specimens positive for influenza ranged from 58?3% to 77?8%. Children aged 2 to 17 years had the highest incidence of influenza-associated visits (range 4?2-28?0 per 1000 people by year), and adults older than 65 years had the lowest (range 0?5-3?5 per 1000 population). Influenza A H3N2, pandemic H1N1, and influenza B equally co-circulated in the first post-pandemic season, whereas H3N2 predominated for the next two seasons. Of patients for whom data was available, influenza vaccination was reported in 3289 (28?7%) of 11 459 patients with influenza-like illness, and antivirals were prescribed to 1644 (13?8%) of 11 953 patients.
INTERPRETATION:
Influenza incidence varied with age groups and by season after the pandemic of 2009 influenza A H1N1. High levels of influenza virus circulation, especially in young children, emphasise the need for additional efforts to increase the uptake of influenza vaccines and antivirals.
FUNDING:
US Centers for Disease Control and Prevention.
Copyright ? 2015 Elsevier Ltd. All rights reserved.
PMID: 26300111 [PubMed - as supplied by publisher]
Incidence of medically attended influenza during pandemic and post-pandemic seasons through the Influenza Incidence Surveillance Project, 2009-13.
Fowlkes A[SUP]1[/SUP], Steffens A[SUP]1[/SUP], Temte J[SUP]2[/SUP], Lonardo SD[SUP]3[/SUP], McHugh L[SUP]4[/SUP], Martin K[SUP]5[/SUP], Rubino H[SUP]6[/SUP], Feist M[SUP]7[/SUP], Davis C[SUP]8[/SUP], Selzer C[SUP]9[/SUP], Lojo J[SUP]10[/SUP], Oni O[SUP]11[/SUP], Kurkjian K[SUP]12[/SUP], Thomas A[SUP]13[/SUP], Boulton R[SUP]14[/SUP], Bryan N[SUP]15[/SUP], Lynfield R[SUP]5[/SUP], Biggerstaff M[SUP]1[/SUP], Finelli L[SUP]1[/SUP]; Influenza Incidence Surveillance Project Working Group.
Author information
Abstract
BACKGROUND:
Since the introduction of pandemic influenza A (H1N1) to the USA in 2009, the Influenza Incidence Surveillance Project has monitored the burden of influenza in the outpatient setting through population-based surveillance.
METHODS:
From Oct 1, 2009, to July 31, 2013, outpatient clinics representing 13 health jurisdictions in the USA reported counts of influenza-like illness (fever including cough or sore throat) and all patient visits by age. During four years, staff at 104 unique clinics (range 35-64 per year) with a combined median population of 368 559 (IQR 352 595-428 286) attended 35 663 patients with influenza-like illness and collected 13 925 respiratory specimens. Clinical data and a respiratory specimen for influenza testing by RT-PCR were collected from the first ten patients presenting with influenza-like illness each week. We calculated the incidence of visits for influenza-like illness using the size of the patient population, and the incidence attributable to influenza was extrapolated from the proportion of patients with positive tests each week.
FINDINGS:
The site-median peak percentage of specimens positive for influenza ranged from 58?3% to 77?8%. Children aged 2 to 17 years had the highest incidence of influenza-associated visits (range 4?2-28?0 per 1000 people by year), and adults older than 65 years had the lowest (range 0?5-3?5 per 1000 population). Influenza A H3N2, pandemic H1N1, and influenza B equally co-circulated in the first post-pandemic season, whereas H3N2 predominated for the next two seasons. Of patients for whom data was available, influenza vaccination was reported in 3289 (28?7%) of 11 459 patients with influenza-like illness, and antivirals were prescribed to 1644 (13?8%) of 11 953 patients.
INTERPRETATION:
Influenza incidence varied with age groups and by season after the pandemic of 2009 influenza A H1N1. High levels of influenza virus circulation, especially in young children, emphasise the need for additional efforts to increase the uptake of influenza vaccines and antivirals.
FUNDING:
US Centers for Disease Control and Prevention.
Copyright ? 2015 Elsevier Ltd. All rights reserved.
PMID: 26300111 [PubMed - as supplied by publisher]