224749 Pre-symptomatic healthcare worker transmission of pandemic (H1N1) influenza in acute care settings

Tuesday, November 9, 2010

Patricia Marquez, MPH , Los Angeles County Department of Public Health, Acute Communicable Disease Control, Los Angeles, CA
Dawn Terashita, MD, MPH , Los Angeles County Department of Public Health, Acute Communicable Disease Control, Los Angeles, CA
L'Tanya English, RN/MPH , Los Angeles County Department of Public Health, Acute Communicable Disease Control, Los Angeles, CA
Nosocomial influenza transmission is a concern in healthcare settings. In 2009, Los Angeles County Department of Public Health (DPH) investigated two outbreaks of pandemic (H1N1) influenza in acute care hospitals where transmission occurred during the pre-symptomatic infectious period from healthcare workers (HCW) to high-risk patients prior to release of the vaccine. Outbreak 1 occurred in July in the hematology-oncology ward of Facility A. The facility reported two nosocomial influenza cases diagnosed with pandemic influenza via rRT-PCR with onset five days apart. DPH investigation revealed HCW 1, prior to developing influenza-like illness, provided care to Case 1 for several days; Case 1 developed symptoms the same day as HCW 1. Indirect contact between Case 1 and Case 2 occurred through the parent of Case 2. HCW 1 was not tested for influenza. Both cases subsequently expired. Outbreak 2 occurred in July in the neonatal intensive care unit of Facility B. Three infants with influenza A (two confirmed as pandemic) were identified within a 24 hour period. DPH investigation revealed four ill HCWs. HCW 1 cared for Case 1 and Case 2 for two days prior to onset of illness. Three other HCWs who cared for Cases 2 and 3 became symptomatic 1-2 days after HCW 1. HCWs were not tested for influenza, and none worked while symptomatic. All infants recovered uneventfully. Both outbreaks demonstrate the possible transmission of influenza from pre-symptomatic HCWs and highlight that enhanced personal hygiene is critical for HCWs in high-risk patient settings, especially in the absence of an effective vaccine.

Learning Areas:
Epidemiology
Protection of the public in relation to communicable diseases including prevention or control
Provision of health care to the public

Learning Objectives:
1. Discuss the implications of breakdowns in infection control practices on patient safety 2. Explain the importance of healthcare worker influenza vaccination 3. Assess atypical influenza symptoms among hospitalized high-risk infants and children.

Keywords: Outbreaks, Epidemiology

Presenting author's disclosure statement:

Qualified on the content I am responsible for because: I am qualified to present because I am the epidemiologist in a unit that conducts outbreak investigations in Los Angeles County acute care facilities.
Any relevant financial relationships? No

I agree to comply with the American Public Health Association Conflict of Interest and Commercial Support Guidelines, and to disclose to the participants any off-label or experimental uses of a commercial product or service discussed in my presentation.