Vaccination of Health Care Workers to Protect Patients at Increased Risk for Acute Respiratory Disease

Gayle P. Dolan

, Rebecca C. Harris, Mandy Clarkson, Rachel Sokal, Gemma Morgan, Mitsuru Mukaigawara, Hiroshi Horiuchi, Rachel Hale, Laura Stormont, Laura Béchard-Evans, Yi-Sheng Chao, Sergey Eremin, Sara Martins, John S. Tam, Javier Peñalver, Arina Zanuzadana, and Jonathan S. Nguyen-Van-Tam

Author affiliations: University of Nottingham, Nottingham, UK (G.P. Dolan, R. Hale, J.S. Nguyen-Van-Tam); World Health Organization, Geneva, Switzerland (R.C. Harris, M. Mukaigawara, L. Stormont, Laura Béchard-Evans, Y.-S. Chao, S. Eremin, S. Martins, J.S. Tam, J. Peñalver); National Health Service Derbyshire County, Chesterfield, UK (M. Clarkson, R. Sokal); Health Protection Agency South West, Gloucester, UK (G. Morgan); Tokyo Medical Dental University, Tokyo, Japan (H. Horiuchi); and University of Bielefeld, Bielefeld, Germany (A. Zanuzadana)

Abstract

Health care workers (HCWs) may transmit respiratory infection to patients. We assessed evidence for the effectiveness of vaccinating HCWs to provide indirect protection for patients at risk for severe or complicated disease after acute respiratory infection. We searched electronic health care databases and sources of gray literature by using a predefined strategy. Risk for bias was assessed by using validated tools, and results were synthesized by using a narrative approach. Seventeen of the 12,352 identified citations met the full inclusion criteria, and 3 additional articles were identified from reference or citation tracking. All considered influenza vaccination of HCWs, and most were conducted in long-term residential care settings. Consistency in the direction of effect was observed across several different outcome measures, suggesting a likely protective effect for patients in residential care settings. However, evidence was insufficient for us to confidently extrapolate this to other at-risk patient groups.

Respiratory disease is a leading cause of deaths worldwide, and influenza and pneumococcal infections are major contributors. Certain groups, such as persons >65 years of age or with chronic underlying health problems (1) are particularly vulnerable to severe respiratory disease and have poorer outcomes after infection than does the general population. These persons are likely to be frequent users of health care facilities, and outbreaks have been described in a range of high-risk environments, including acute care (2,3), pulmonary (4), and infectious diseases wards (5); organ transplant departments (6); children’s wards (7,8); neonatal intensive care units (9); and nursing homes (10,11). Severe respiratory infections often occur despite high vaccine coverage rates among patients, suggesting that seroconversion is suboptimal (10). Although the origin of infection often is difficult to establish, evidence from some outbreaks (5,7,10–14) suggests that transmission from HCWs to patients is likely.
It is estimated from previous influenza seasons that ≈20% of HCWs have evidence of infection (15), although not necessarily acquired in the workplace. Young healthy adults often have asymptomatic infection, and ≈28%–59% might experience subclinical infection (15). Many persons with mild or subclinical illness continue to work while infectious, and even when illness is recognized, virus might be shed before symptom onset. In a randomized controlled trial among health care professionals, Wilde et al. demonstrated that influenza vaccine was 88% efficacious for reducing serologically confirmed influenza A infection and 89% efficacious for reducing serologically confirmed influenza B infection (16). Therefore, vaccination of HCWs has been widely recommended to provide direct protection for themselves and indirect protection for their patients (1,17).
Despite efforts to encourage influenza vaccination of HCWs, coverage has been historically poor. Recently, ethical arguments for mandatory influenza vaccination have been raised that focus not only on the direct and indirect benefits to staff and patient health but also on the economic consequences. Burls et al. (18) suggested that at a cost of £51–£405 (US$85–$675) per life-year saved, mandatory vaccination is likely to be cost-effective. However, evidence for the effectiveness of vaccinating HCWs for protecting vulnerable patients is limited.
Two recent systematic reviews considered the evidence for indirect protection of vulnerable patient groups after staff influenza vaccination (18,19). They suggest that vaccination of HCWs might be effective for reducing death and influenza-like illness (ILI) among elderly residents, but we are unaware of comparable data related to other at-risk groups. We aimed to identify and assess further evidence for the effect of vaccinating HCWs on patient groups most vulnerable to severe or complicated respiratory illness.

Respiratory infections article
Volume 18, Number 8–August 2012

Vaccination of Health Care Workers to Protect Patients at Increased Risk for Acute Respiratory Disease

MEDSCAPE CME

Medscape, LLC is pleased to provide online continuing medical education (CME) for this journal article, allowing clinicians the opportunity to earn CME credit.
This activity has been planned and implemented in accordance with the Essential Areas and policies of the Accreditation Council for Continuing Medical Education through the joint sponsorship of Medscape, LLC and Emerging Infectious Diseases. Medscape, LLC is accredited by the ACCME to provide continuing medical education for physicians.
Medscape, LLC designates this Journal-based CME activity for a maximum of 1 AMA PRA Category 1 Credit(s)^TM. Physicians should claim only the credit commensurate with the extent of their participation in the activity.
All other clinicians completing this activity will be issued a certificate of participation. To participate in this journal CME activity: (1) review the learning objectives and author disclosures; (2) study the education content; (3) take the post-test with a 70% minimum passing score and complete the evaluation at www.medscape.org/journal/eid ; (4) view/print certificate.

Release date: July 20, 2012; Expiration date: July 20, 2013

Learning Objectives

Upon completion of this activity, participants will be able to:
• Assess the impact of influenza infection among health care workers
• Analyze the methodology of research into vaccination of health care workers
• Evaluate the effects of health care worker vaccination on rates of influenza infection among patients
• Distinguish other patient-related outcomes of health care worker vaccination programs

CME Editor

Karen L. Foster, Technical Writer/Editor, Emerging Infectious Diseases. Disclosure: Karen L. Foster has disclosed no relevant financial relationships.

CME AUTHOR

Charles P. Vega, MD, Health Sciences Clinical Professor; Residency Director, Department of Family Medicine, University of California, Irvine. Disclosure: Charles P. Vega, MD, has disclosed no relevant financial relationships.

AUTHORS

Disclosures: Gayle P. Dolan, MBChB; Mandy Clarkson; Rachel Sokal; Gemma Morgan; Mitsuru Mukaigawara; Hiroshi Horiuchi, DDS, PhD; Rachel Hale; Laura Stormont; Laura Béchard-Evans; Sergey Eremin, MD, PhD; Sara Martins; John S. Tam; Javier Peñalver, MD; and Arina Zanuzadana have disclosed no relevant financial relationships. Rebecca C. Harris, MD, has disclosed the following relevant financial relationships: served as an advisor or consultant for GlaxoSmithKline Biologicals, which began after major contributions to manuscript. Yi-Sheng Chao has disclosed the following relevant financial relationships: served as a consultant for Gere Biotechnology Ltd., Co., to review biomedical studies. Jonathan S. Nguyen-Van-Tam, MD, PhD, has disclosed the following relevant financial relationships: served as an advisor or consultant for F. Hoffman-LaRoche, Baxter AG, GlaxoSmithKline, and AstraZeneca, for which out of pocket travel expenses were reimbursed; currently in receipt of research funding from F. Hoffmann-La Roche, GlaxoSmithKline, and AstraZeneca.