Mandatory Influenza Vaccination for Healthcare Workers: Agreeing to Agree

This is a guest post from Sanjay Saint, MD, MPH, the George Dock Professor of Internal Medicine at the University of Michigan, the Director of the VA/University of Michigan Patient Safety Enhancement Program and the Chief of Medicine at the Ann Arbor VA Medical Center.


I begin by thanking my friend and colleague, Dr. Eli Perencevich, for allowing me use of “Controversies in Hospital Infection Prevention” for my first blog post. 

Our recent editorial in The Wall Street Journal on mandatory flu vaccination for healthcare workers elicited strong opinions, especially on social media. The impetus for our editorial was a recent paper published in Infection Control and Hospital Epidemiology in which we found through a national survey of lead infection preventionists that 42.7% of nonfederal hospitals had a policy mandating flu vaccinations for healthcare workers while only 1.3% of VA hospitals did.

In his 22 December 2015 blog post, Eli clarified his position by writing that he is “in favor of mandating influenza vaccination of healthcare workers (for now)”. I am in agreement. While the data supporting mandatory healthcare worker flu vaccination is perhaps not as robust as researchers would like – when is it? – in my opinion, it is compelling enough to move forward unless new data emerge that reveal the mandate to be unnecessary or ineffective.

What are the most compelling studies supporting mandatory vaccinations?

The first is a systematic review from Faruque Ahmed, PhD -- a senior scientist in the National Center for Immunization and Respiratory Diseases at the Centers for Disease Control and Prevention (CDC) – and four other CDC researchers.  I paste below the Results and Conclusions from their abstract:

Results. We identified 4 cluster randomized trials and 4 observational studies conducted in long-term care or hospital settings. Pooled risk ratios across trials for all-cause mortality and influenza-like illness were 0.71 (95% confidence interval [CI], .59–.85) and 0.58 (95% CI, .46–.73), respectively; pooled estimates for all-cause hospitalization and laboratory-confirmed influenza were not statistically significant. The cohort and case-control studies indicated significant protective associations for influenza-like illness and laboratory-confirmed influenza. No studies reported harms to patients. Using GRADE, the quality of the evidence for the effect of HCP vaccination on mortality and influenza cases in patients was moderate and low, respectively. The evidence quality for the effect of HCP vaccination on patient hospitalization was low. The overall evidence quality was moderate.

Conclusions. The quality of evidence is higher for mortality than for other outcomes. HCP influenza vaccination can enhance patient safety.

How could influenza vaccination affect all-cause mortality? I am not sure but previous studies have found influenza vaccination reduces cardiovascular events and venous thromboembolism.  How vaccination may affect these outcomes is not known - but it isn't irrational to also include all-cause mortality as an outcome given the myriad benefits of influenza vaccination.

The second study (not included in the aforementioned systematic review, but mentioned in the postscript), is a cluster randomized trial of hospitalized patients in the Netherlands published in June 2013. I paste the abstract below:

Nosocomial influenza is a large burden in hospitals. Despite recommendations from the World Health Organization to vaccinate healthcare workers against influenza, vaccine uptake remains low in most European countries. We performed a pragmatic cluster randomised controlled trial in order to assess the effects of implementing a multi-faceted influenza immunisation programme on vaccine coverage in hospital healthcare workers (HCWs) and on in-patient morbidity. We included hospital HCWs of three intervention and three control University Medical Centers (UMCs), and 3,367 patients. An implementation programme was offered to the intervention UMCs to assess the effects on both vaccine uptake among hospital staff and patient morbidity. In 2009/10, the coverage of seasonal, the first and second dose of pandemic influenza vaccine as well as seasonal vaccine in 2010/11 was higher in intervention UMCs than control UMCs; all p<0 .05="" span=""> At the internal medicine departments of the intervention group with higher vaccine coverage compared to the control group, nosocomial influenza and/or pneumonia was recorded in 3.9% and 9.7% of patients of intervention and control UMCs, respectively (p=0.015). Though potential bias could not be completely ruled out, an increase in vaccine coverage was associated with decreased patient in-hospital morbidity from influenza and/or pneumonia.

A third study (from another group in the Netherlands) used decision-analytic modeling to estimate the effects of healthcare worker influenza vaccination in the hospital setting.  The abstract is below:

Nowadays health care worker (HCW) vaccination is widely recommended. Although the benefits of this strategy have been demonstrated in long-term care settings, no studies have been performed in regular hospital departments. We adapt a previously developed model of influenza transmission in a long-term care nursing home department to study the effects of HCW vaccination in hospital wards. We study both the effectiveness and efficiency in reducing the hazard rates of influenza virus infection for patients. Most scenarios under study show a similar or higher impact of hospital HCW vaccination than has been predicted for the long-term care nursing home department. Therefore, it seems justified to extend the recommendations for HCW vaccination, based on results in the long-term care setting, to short-term care settings as well.

Eli recently wrote: “There is no data supporting the benefits of healthcare worker vaccination in acute care hospital settings…We are basing acute-care hospital policy on one observational study.” I would thus modify this by stating we are basing acute-care hospital policy on a cluster randomized trial done in a hospital setting, an observational study performed in a hospital setting, a decision analytic model explicitly focusing on an acute-care setting, and 4 randomized studies from long-term care settings as part of a well-done systematic review.

While the opinion of professional societies is not always correct, I am impressed by the strong support in the scientific community for mandatory influenza vaccination for healthcare workers.  The list of societies that support mandatory influenza vaccination for healthcare personnel includes: American Academy of Family Physicians, American Academy of Pediatrics, American College of Physicians, American Hospital Association, American Public Health Association, Association for Professionals in Infection Control and Epidemiology, Infectious Diseases Society of America, National Patient Safety Foundation, and Society for Healthcare Epidemiology for America.

Finally, is mandating flu vaccination for healthcare workers ethical? For guidance I turn to Arthur L. Caplan, PhD, one of the country’s foremost medical ethicists and whose opinion about white coats was highlighted on this blog. Writing in 2013, Professor Caplan states:

“The moral case for limiting health care workers' choice concerning influenza vaccination rests on 4 principles: the professional duty to put patients' interests first, the obligation to do no harm, the requirement to protect those who cannot protect themselves, and the obligation to set a good example for the public. It is hard to see how the invocation of personal liberty claimed by some health care workers who oppose mandates could overcome this powerful “four-legged” moral case in support of an influenza vaccination mandate…Mandating vaccination is consistent with professional ethics; benefits many, some of whom must rely on health care workers to protect them; and sets an example that permits honest engagement with the public in educating them to do the right thing about all recommended vaccines.”


  1. Though the science is still in debate, what I see is we should at least try to do what is best for our Veterans. Sometimes it's that simple.

  2. Every time we mandate a QI intervention that lacks high-level evidence we shoot ourselves in the foot and undermine all of QI. We still lack buy-in from many physicians and these mandates simply add fuel to their fire, as they dismiss QI with a broad brush. The level of supporting evidence and the strength of the recommendation must be tightly linked. We can all name QI mandate blunders, which have harmed the credibility of the QI field, and I fear that mandatory influenza vaccination may be the next one.


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