Canadian call for health worker flu shots stirs debate

Nov 6, 2012 (CIDRAP News) – A recent editorial calling for requiring influenza shots in healthcare workers (HCWs) has stirred debate in the pages of the Canadian Medical Association Journal (CMAJ), with two groups of researchers questioning the quality of the evidence that the vaccinations protect patients.

Last week CMAJ published an editorial endorsing a flu-shot requirement for HCWs, with exemptions granted only for medical contraindications or "deeply held religious or philosophical convictions." Ken Flegel, MDCM, MSc, senior associate editor of the journal, wrote that high rates of HCW vaccination reduce patient mortality and save money.

"Our patients' lives depend on this change," he wrote.

Today CMAJ published replies by two groups of researchers who took issue with the evidence cited by Flegel, plus a reply from a Canadian advocacy group that raised similar questions and also expressed concern about vaccine side effects.

A growing number of US health systems and hospitals now require their employees to receive a flu-shot or else wear a mask during flu season. In addition, a number of states require healthcare facilities to take steps to promote flu immunizations among their employees, according to information from the Centers for Disease Control and Prevention (CDC).

A CDC chart says that Alabama requires hospitals to mandate flu vaccination for their staff members. Ten other states (California, Illinois, Maine, Maryland, Massachusetts, Nebraska, New Hampshire, Oklahoma, Rhode Island, and Tennessee) require healthcare facilities to offer flu shots and, in most cases, to require employees sign a form if they decline the immunization, according to the CDC.

In Canada, Public Health Ontario recently recommended that healthcare facilities require flu shots for their staffs, according to the CMAJ editorial.

Among the arguments Flegel made in the editorial were these:

  • Flu vaccines are about 86% efficacious when they are well matched to circulating flu strains
  • Four randomized trials showed that high flu immunization rates in long-term care facility (LTCF) workers yielded a 5% to 20% reduction in overall seasonal mortality among residents
  • One cost-benefit analysis suggested that every $1,000 (US) spent on vaccinating HCWs saved $1,600
  • Flu strains with the potential to induce Guillain-Barre syndrome (GBS) "are generally avoided in creation of the vaccine"

In reply, several members of the Cochrane Collaboration, an international network of researchers who examine the evidence for medical interventions, said Flegel cited an outdated version of their flu-vaccine review, leading to inaccuracies on the benefits of HCW vaccination.

The group, led by Peter Doshi, PhD, of Johns Hopkins University, said Flegel cited a 2006 Cochrane review rather than the 2010 review in discussing the benefits in LTCFs. In the 2010 review, Doshi said he and his colleagues concluded that there was no evidence that vaccinating only HCWs prevents lab-confirmed flu, pneumonia, and death from pneumonia in LTCFs.

The editorial also drew objections from experts at the University of Minnesota's Center for Infectious Disease Research and Policy, which publishes CIDRAP News.

CIDRAP Director Michael T. Osterholm, PhD, MPH, and staff member Nicholas S. Kelley, PhD, wrote that they strongly support flu immunization for HCWs, but said the stated efficacy of 86% when the vaccine matches well with circulating strains is inaccurate.

They noted that their own meta-analysis of flu vaccine efficacy and effectiveness studies, published last year in Lancet Infectious Diseases, concluded that inactivated vaccine provided about 59% protection in healthy, working-age adults and that the vaccine-virus match made little difference. (The meta-analysis was updated last month in a lengthy CIDRAP report on flu vaccines, which called for a major effort to develop "game-changing" vaccines.)

In addition, they said that two of the four randomized trials that Flegel cited concerning protection in LTCFs do not support the claim, and the other two provide only weak evidence for it.

Osterholm and Kelley made two further points:

  • The cost savings cited by Flegel are not mentioned in the reference he used, and most flu-vaccine cost-effectiveness figures are based on overestimations of vaccine efficacy.
  • There is no way to select flu strains that reduce the risk of GBS, because the reason that flu vaccines may cause the paralytic condition is still unclear.

The other reply was written by Susan Fletcher, president of the Vaccination Risk Awareness Network Inc., a Canadian group that questions the safety of vaccines. She used information from the recent CIDRAP flu-vaccine report to question Flegel's assertions about vaccine efficacy and "herd immunity" to flu.

Fletcher also questioned the cost-effectiveness of flu vaccination for HCWs and argued that vaccine-related adverse events are probably under reported for various reasons, including consumers' unawareness that they can report them.

See also:

Oct 29 CMAJ editorial

Replies to editorial, published Nov 5 and 6

CDC chart of state requirements on flu immunization for hospital workers

Oct 15 CIDRAP News story "Report: Complacency, misperception stymie quest for better flu vaccines"

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