Study Challenges Flu Shot Mandates
Research findings support AOHP position on controversial issue
April 1, 2017
A new research analysis that
concludes there is insufficient evidence to make seasonal vaccinations a condition of employment essentially validates the position taken on this controversial subject by the Association for Occupational Health Professionals in Healthcare (AOHP).
“We do support a mandate to ‘provide’ flu vaccinations for employees, but we have not made the statement that they should be mandatory and you lose your job if you don’t take it,” says Mary Bliss, RN, AOHP executive president. “We have not taken that position.”
Using a policy that requires healthcare workers to wear a mask for patient care if they are not immunized, Bliss achieves annual influenza immunization rates above 90% without making the shot a condition of employment as coordinator of employee health services at UnityPoint Health-Methodist/Proctor Hospital in Peoria, IL.
In the new study, Canadian researchers report1 that the four randomized controlled trials (RCTs)2-5 commonly cited to justify compulsory immunization lack scientific rigor and overstate the protective benefit to patients. The four trials were conducted in long-term care facilities, but have generally been extrapolated to support flu immunization requirements in acute care and other settings. Among other benefits, the studies generally link reductions in resident mortality to higher staff flu vaccination rates.
With healthcare worker vaccination rates lagging in most hospitals, several facilities began mandating immunization several years ago in what has since become a national trend. Mandatory vaccination policies are driving a trend that saw 91% of hospital workers immunized during the last flu season — a far cry from the lagging levels of the voluntary flu shot era, the CDC reports.6
As the RCTs are often cited in support of such policies, the new Canadian study attacks a core rationale for making flu shots a condition of healthcare employment. After an elaborate analysis using the “dilution” principal of mathematics, the authors of the study conclude that there is insufficient scientific evidence to mandate flu vaccine as a condition of healthcare employment.
“It is unsupported by science,” says the lead author of the study, Gaston De Serres, MD, of the Institut national de santé publique du Québec in Quebec City, Canada. “When you are mandating a public health intervention, you better be sure that the burden of disease that you want to prevent is substantial. At this time, no one knows how many patients are infected annually in the United States by unvaccinated healthcare workers. Nobody knows.”
Prevented Mortality Overstated?
The upshot of the paper is that the RCTs vastly overstate the protective effect to patients being treated by immunized healthcare workers, particularly in the area of prevented deaths. In contrast to the “mathematically impossible” prevented-mortality estimates reported in the papers, De Serres and colleagues project that it actually may take from 6,000 to 32,000 healthcare worker immunizations to prevent one patient death from influenza.
“We found that the four studies were reporting results for [reductions in] all-cause mortality that were not 50%, not even 100% greater,” De Serres says. “They were 10 to 12 times greater than could plausibly be achieved if the vaccine was 60% effective.”
The paper has the devastating cumulative effect of a legal argument, and indeed concludes with a disclosure endnote that several of the authors have provided expert testimony during legal challenges to mandatory flu vaccination policies in Canada. In a recent case that surprised some, six healthcare workers fired for refusing mandatory flu shots for religious reasons won back pay and offers of reinstatement from Saint Vincent Hospital in Erie, PA, after their case was taken up by the U.S. Equal Employment Opportunity Commission. (For more information, see the February 2017 issue of HEH.)
“Each of the four cluster RCTs used to champion compulsory HCW influenza vaccination policies reports benefits that are mathematically impossible under any reasonable hypothesis of indirect vaccine effect,” the Canadian authors conclude. “Through this detailed critique and quantification of the evidence, we conclude that policies of enforced influenza vaccination of HCWs to reduce patient risk lack a sound empirical basis. In that context, an intuitive sense that there may be some evidence in support of some patient benefit is insufficient scientific basis to ethically override individual HCW rights. While HCWs have an ethical and professional duty not to place their patients at increased risk, so also have advocates for compulsory vaccination a duty to ensure that the evidence they cite is valid and reliable, particularly in the absence of good scientific estimates of patient impact.”
The author of one of the randomized controlled trials on the protective effect of immunizing healthcare workers against influenza defended his research, but emphasized it applies only to long-term care settings. In an article7 published along with the Canadian study, Andrew C. Hayward, MD, a member of the National Institute for Health and Clinical Excellence, defended his 2006 RCT.
“In our discussion, based on our own findings and those from other studies, we concluded that healthcare worker vaccination provides an important level of resident protection in long-term care facility settings,” he concluded. “While we claimed that the findings may be generalizable to other settings, we did not intend to imply that the extent of the benefit would be similar in other settings. Indeed, we think the effect is likely to be substantially greater in long-term care facilities for frail elderly residents than in the acute care setting or in long-term care facilities catering for less frail patients.”
Although current data are inadequate to support enforced healthcare influenza vaccination, they do not refute voluntary vaccination or other more broadly protective practices such as staying home or masking when acutely ill, De Serres notes.
“There is a real problem with the healthcare system and it is going to work when you are sick — not only for influenza, but the other respiratory viruses,” De Serres says. “You don’t want your professionals — your nurses caring for patients — to be at the bedside when they are sick. And that really is not often addressed. It appears to be a sort of magical solution to use the influenza vaccine and coerce vaccination to demonstrate that you really care for patients.”
Presenteeism is a widely reported problem that challenges short-staffed facilities, in part fueled by the prevailing mentality that healthcare workers don’t want to let their colleagues down by failing to report for duty.
“I found it interesting at the end of the discussion [the authors] say we ought to think about other things in addition to voluntary immunization, like staying home when sick or masking,” says William Schaffner, MD, a professor of preventive medicine at Vanderbilt University in Nashville. “I find it stunning that they, in effect, recommend those interventions, over which the data are much less [established] than for influenza immunization.”
Having long acknowledged the flu vaccine is imperfect and subject to seasonal fluctuations in efficacy, Schaffner nevertheless favors mandatory immunization of healthcare workers despite the Canadian study.
“If you take the RCTs all by themselves — off to the side — our Canadian colleagues have a point, but I don’t believe their point carries the day,” he says. “They only looked at the RCTs. These provide the most rigorous data, but we recognize that RCTs on this question are hugely difficult to do. If we are going to address the entire question of the scientific, professional, and ethical basis of mandates, you ought to look at the entire body of evidence. There are any number of observational studies of one kind or another that could be added. Obviously they have profound scientific limitations also, but at least in my mind they add to the body of evidence that makes mandatory influenza immunization more than reasonable.”
A past president of the National Foundation for Infectious Diseases and a frequent host of its annual flu vaccine press conference, Schaffner has long advocated immunization for healthcare workers and others as recommended by the CDC. As mentioned, the Canadian study focused on the questionable prevented-mortality estimates linked to vaccinating healthcare workers, but there are secondary benefits that should also be noted, he says.
“That is not the only issue to consider,” Schaffner says. “We also don’t want to make patients ill with influenza, and that issue is not addressed. They put much of their emphasis on the most severe endpoint. Similarly, they didn’t look at any other potential benefits of immunization such as worker absenteeism during an influenza outbreak, or the extended [protective] benefit to the worker’s family. These may not be the primary issues underlying a mandate, but they sure have come up in virtually every discussion of influenza vaccination mandates that I have read or written about.”
Schaffner says the issue boils down to a central question: How much evidence is necessary in order to make a recommendation for a mandate?
“From my point of view, the accumulated evidence, including and beyond the RCTs, is sufficient on a scientific, professional, and ethical basis,” he says. “There must be 20 professional societies now that have agreed with this [mandated] position.”
On the contrary, the findings are compelling enough that professional groups should rethink their endorsement of mandatory flu vaccination, says Michael Edmond, MD, clinical professor of internal medicine and infectious diseases at the University of Iowa in Iowa City.
“I don’t want this to be confused with any kind of anti-vaccine rhetoric, but to me it kind of plays into it,” says Edmond, who was not involved in the study. “The anti-vaccine rhetoric focuses on false claims of adverse effects of vaccines, and that is completely wrong. But on the other side of it, we have to acknowledge the shortcomings of vaccines in an honest way as well. I would argue that we have to look at the science on both sides of it and do what the science tells us to do.”
With any intervention to improve quality or patient safety, the expectation for compliance should be directly related to the evidence, he says.
“In this case, we don’t have a high level of evidence,” he says. “Therefore, to mandate it — and in this case, to say if you are not in compliance you will be fired from your job — to me is just an unacceptable situation.”
- De Serres G, Skowronski DM, Ward BJ, et al. (2017) Influenza Vaccination of Healthcare Workers: Critical Analysis of the Evidence for Patient Benefit Underpinning Policies of Enforcement. PLoS ONE 2017; 12(1): doi:10.1371/journal.pone.0163586
- Potter J, Stott DJ, Roberts MA, et al. Influenza vaccination of health care workers in long-term-care hospitals reduces the mortality of elderly patients. J Infect Dis 1997; 175: 1–6.
- Carman WF, Elder AG, Wallace LA, et al. Effects of influenza vaccination of health-care workers on mortality of elderly people in long-term care: a randomised controlled trial. Lancet 2000;355:93–97.
- Hayward AC, Harling R, Wetten S, et al. Effectiveness of an influenza vaccine program for care home staff to prevent death, morbidity, and health service use among residents: cluster randomised controlled trial. Brit Med J 2006;333:1241. doi: 10.1136/bmj.39010.581354.55.
- Lemaitre M, Meret T, Rothan-Tondeur M, et al. Effect of influenza vaccination of nursing home staff on mortality of residents: a cluster-randomized trial. J Am Geriat Soc 2009; 57:1580–1586.
- CDC Influenza Vaccination Coverage Among Health Care Personnel — United States, 2015–16 Influenza Season. MMWR 2016; 65(38):1026–1031.
- Hayward AC. Influenza Vaccination of Healthcare Workers Is an Important Approach for Reducing Transmission of Influenza from Staff to Vulnerable Patients. PLoS ONE 2017;12(1): e0169023. doi:10.1371/journal.pone.016902.
A new research analysis that concludes there is insufficient evidence to make seasonal vaccinations a condition of employment essentially validates the position taken on this controversial subject by the Association for Occupational Health Professionals in Healthcare.
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