Program Schedule

Influenza Among Afebrile and Vaccinated Healthcare Workers

Session: Oral Abstract Session: Influenza Vaccines
Thursday, October 9, 2014: 2:30 PM
Room: The Pennsylvania Convention Center: 111-AB


During the 2013-2014 influenza season, an aggressive influenza surveillance program among healthcare workers (HCWs) was implemented at our 600-bed hospital in Chicago after a healthcare worker was diagnosed with influenza in the absence of fever.  The hospital's routine sick policy prohibited febrile HCWs from working, but not those with respiratory symptoms in the absence of fever. Given the risk of influenza transmission to patients from afebrile employees with influenza, a temporary policy for management of HCW with respiratory symptoms that included mandatory influenza testing and use of a mask while at work was implemented.


 From January 6 through February 28, 2014, all HCWs with any respiratory symptoms, including cough, sore throat, runny nose, or congestion, were required to be tested for influenza.  Flocked nasal swabs were collected and underwent PCR testing for influenza and other respiratory viruses. At the time of testing, HCWs completed a screening questionnaire describing their symptoms and vaccination history and had their temperature measured. HCWs whose tests were positive for influenza were required to refrain from work for 7 days or until symptoms resolved, which ever was longest.  Work restrictions were also implemented for employees who tested positive for other viruses depending on work area.  Employees with negative tests were required to use a mask at work at all times. 


Of the 446 HCWs who underwent influenza testing, 37 were positive for influenza A (8.3%) (Figure 1). 35 (95%) samples were identified as H1N1 2009 pandemic strain. Of the HCWs with influenza, 41% (15/37) did not have a fever (Figure 2). 43% (16/37) received the 2013-2014 influenza vaccine prior to the onset of their symptoms  (Figure 3). Among the 16 vaccinated HCWs who developed influenza, 8 (50%) did not have a fever before their diagnosis.


Nearly half of HCWs with influenza were afebrile prior to their diagnosis. HCWs with respiratory symptoms but no fever may pose a risk of influenza transmission to patients and coworkers. To prevent the spread of influenza, hospitals should consider stringent infection control measures for HCWs and patients with any respiratory symptoms, even if no fever is present.

Figure 1:

Jessica P. Ridgway, MD1, Allison H. Bartlett, MD, MS2, Sylvia Garcia-Houchins, RN, MBA, CIC3, Sean Cariņo, MPH3, Aurea Enriquez, M(ASCP), CIC3, Rachel Marrs, MSN, CIC3, Cynthia Perez, M(ASCP), CIC3, Mona Shah, BS, CIC3, Caroline Guenette, MS4, Steve Mosakowski5, Kathleen G. Beavis, MD6 and Emily Landon, MD1, (1)Infectious Diseases & Global Health, University of Chicago, Chicago, IL, (2)Pediatrics (Infectious Diseases), University of Chicago Medicine, Chicago, IL, (3)Infection Control Program, The University of Chicago Medicine, Chicago, IL, (4)Occupational Medicine, The University of Chicago Medicine, Chicago, IL, (5)The University of Chicago Medicine, Chicago, IL, (6)Microbiology, The University of Chicago Medicine, Chicago, IL


J. P. Ridgway, None

A. H. Bartlett, None

S. Garcia-Houchins, None

S. Cariņo, None

A. Enriquez, None

R. Marrs, None

C. Perez, None

M. Shah, None

C. Guenette, None

S. Mosakowski, None

K. G. Beavis, None

E. Landon, None

See more of: Influenza Vaccines
See more of: Oral Abstract Session

Findings in the abstracts are embargoed until 12:01 a.m. EDT, Oct. 8th with the exception of research findings presented at the IDWeek press conferences.

Sponsoring Societies:

© 2014, All Rights Reserved.

Follow IDWeek