tetano
Editor, Senior Moderator
Clin Infect Dis
. 2020 Aug 4;ciaa1109.
doi: 10.1093/cid/ciaa1109. Online ahead of print.
Incidence of asymptomatic and symptomatic influenza among healthcare workers: a multicenter prospective cohort study
Thomas B?net[SUP] 1 2 [/SUP], S?lilah Amour[SUP] 1 [/SUP], Martine Valette[SUP] 3 4 [/SUP], Mitra Saadatian-Elahi[SUP] 1 [/SUP], Ludwig Serge Aho-Gl?l?[SUP] 5 [/SUP], Philippe Berthelot[SUP] 6 7 [/SUP], Marie-Agn?s Denis[SUP] 8 9 [/SUP], Jacqueline Grando[SUP] 1 [/SUP], Caroline Landelle[SUP] 10 11 [/SUP], Karine Astruc[SUP] 5 [/SUP], Adeline Paris[SUP] 12 [/SUP], Sylvie Pillet[SUP] 7 [/SUP], Bruno Lina[SUP] 3 4 13 [/SUP], Philippe Vanhems[SUP] 1 2 13 [/SUP], AFP Study Group
Affiliations
Abstract
Background: Influenza is an important cause of viral hospital-acquired infection involving patients, healthcare workers (HCW), and visitors. The frequency of asymptomatic influenza among HCW with possible subsequent transmission is poorly described. The objective is to determine the cumulative incidence of asymptomatic, pauci-symptomatic and symptomatic influenza among HCW.
Method: A multicenter prospective cohort study was done in 5 French university hospitals, including 289 HCW during the 2016-2017 influenza season. HCW had 3 physical examinations (Time [T] 0, before epidemic onset; T.1, before epidemic peak; T.2, T.3 after epidemic peak). A blood sample was taken each time for influenza serology and a nasal swab was collected at T1 and T2 for influenza detection by PCR. Positive influenza was defined as either a positive influenza PCR, and/or virus-specific seroconversion against influenza A, the only circulating virus, with no vaccination record during follow-up. Symptoms were self-reported daily between T1 and T2. Cumulative incidence of influenza was stratified by clinical presentation per 100 HCW.
Findings: Of the 289 HCW included, 278 (96%) completed the entire follow-up. Overall, 62 HCW had evidence of influenza of whom 46?8% were asymptomatic, 41?9% were pauci-symptomatic, and 11?3% were symptomatic. Cumulative influenza incidence was 22?3% (95%CI:17?4%-27?2%). Cumulative incidence of asymptomatic influenza was 5?8% (95%CI: 3?3%-9?2%), 13?7% (95%CI:9?9%-18?2%) for pauci-symptomatic influenza, and 2?9% (95%CI:1?3%-5?5%) for symptomatic influenza.
Interpretation: Asymptomatic and pauci-symptomatic influenza were frequent among HCW, representing 47% and 42% of the influenza burden respectively. These findings highlight the importance of systematic implementation of infection control measures among HCW regardless of respiratory symptoms from preventing nosocomial transmission of influenza.
Trial registration: clinicaltrials.gov identifier: NCT02868658.
Keywords: asymptomatic influenza; healthcare workers; incidence; nosocomial; prospective cohort.
. 2020 Aug 4;ciaa1109.
doi: 10.1093/cid/ciaa1109. Online ahead of print.
Incidence of asymptomatic and symptomatic influenza among healthcare workers: a multicenter prospective cohort study
Thomas B?net[SUP] 1 2 [/SUP], S?lilah Amour[SUP] 1 [/SUP], Martine Valette[SUP] 3 4 [/SUP], Mitra Saadatian-Elahi[SUP] 1 [/SUP], Ludwig Serge Aho-Gl?l?[SUP] 5 [/SUP], Philippe Berthelot[SUP] 6 7 [/SUP], Marie-Agn?s Denis[SUP] 8 9 [/SUP], Jacqueline Grando[SUP] 1 [/SUP], Caroline Landelle[SUP] 10 11 [/SUP], Karine Astruc[SUP] 5 [/SUP], Adeline Paris[SUP] 12 [/SUP], Sylvie Pillet[SUP] 7 [/SUP], Bruno Lina[SUP] 3 4 13 [/SUP], Philippe Vanhems[SUP] 1 2 13 [/SUP], AFP Study Group
Affiliations
- PMID: 32750120
- DOI: 10.1093/cid/ciaa1109
Abstract
Background: Influenza is an important cause of viral hospital-acquired infection involving patients, healthcare workers (HCW), and visitors. The frequency of asymptomatic influenza among HCW with possible subsequent transmission is poorly described. The objective is to determine the cumulative incidence of asymptomatic, pauci-symptomatic and symptomatic influenza among HCW.
Method: A multicenter prospective cohort study was done in 5 French university hospitals, including 289 HCW during the 2016-2017 influenza season. HCW had 3 physical examinations (Time [T] 0, before epidemic onset; T.1, before epidemic peak; T.2, T.3 after epidemic peak). A blood sample was taken each time for influenza serology and a nasal swab was collected at T1 and T2 for influenza detection by PCR. Positive influenza was defined as either a positive influenza PCR, and/or virus-specific seroconversion against influenza A, the only circulating virus, with no vaccination record during follow-up. Symptoms were self-reported daily between T1 and T2. Cumulative incidence of influenza was stratified by clinical presentation per 100 HCW.
Findings: Of the 289 HCW included, 278 (96%) completed the entire follow-up. Overall, 62 HCW had evidence of influenza of whom 46?8% were asymptomatic, 41?9% were pauci-symptomatic, and 11?3% were symptomatic. Cumulative influenza incidence was 22?3% (95%CI:17?4%-27?2%). Cumulative incidence of asymptomatic influenza was 5?8% (95%CI: 3?3%-9?2%), 13?7% (95%CI:9?9%-18?2%) for pauci-symptomatic influenza, and 2?9% (95%CI:1?3%-5?5%) for symptomatic influenza.
Interpretation: Asymptomatic and pauci-symptomatic influenza were frequent among HCW, representing 47% and 42% of the influenza burden respectively. These findings highlight the importance of systematic implementation of infection control measures among HCW regardless of respiratory symptoms from preventing nosocomial transmission of influenza.
Trial registration: clinicaltrials.gov identifier: NCT02868658.
Keywords: asymptomatic influenza; healthcare workers; incidence; nosocomial; prospective cohort.