The Editor
Vancouver Sun
Nov. 16, 2012

We are writing as Public Health Physicians to respond to and comment on Dr. Jefferson's letter on the Cochrane Collaboration's review of the effectiveness of vaccinating health care workers as a means of protecting vulnerable patients or residents of long term care facilities.

Dr. Jefferson misquotes Dr. Kendall as stating that the Cochrane reviews "reports that vaccinating health care workers protects patients from influenza, pneumonia, doctor's visits, hospitalizations, and even death." Dr. Kendall did not state that. He stated, rather, that the Cochrane review referenced peer-reviewed studies that reported these positive findings, and indeed the Cochrane review did reference these studies.

A variety of studies have shown the benefits of immunization of health care workers. In two observational studies lower health care worker immunization rates were associated with higher rates of laboratory-confirmed hospital-acquired influenza. The Cochrane review is but one of many studies. That paper ended up pooling various results out of 4 randomized controlled trials and one cohort study.  It was not able to demonstrate that influenza immunization of health care workers in those studies reduced laboratory-confirmed influenza in residents, but it did show that these studies report a reduction in deaths from influenza-like illness, deaths from all causes, and GP consultation for influenza -like illness. It then dismissed those results since the reviewers had decided that only laboratory-proven influenza, lower respiratory tract infections and deaths from pneumonia were of primary concern to them, a very narrow outcome of interest.  Many other agencies and experts have found that, if one considers all of the evidence, influenza immunization of health care workers has benefits for the workers and their patients.

In 2011, the Canadian National Advisory Committee on Immunization (NACI) stated that "Influenza infection not only causes primary illness but can also lead to severe secondary medical complications, including viral pneumonia, secondary bacterial pneumonia and worsening of underlying medical conditions.  In addition, influenza testing is not often sought to confirm the diagnosis or may be sought late."  A recent review presented at the Canadian Cardiovascular Congress (2012) found that influenza vaccine may reduce the risk of major adverse cardiac events by up to 50%.   Dismissing all studies that don't include laboratory testing for influenza will miss the clear benefits of immunization.  In fact, "influenza-like illness" is an international standard for tracking the spread of influenza in populations and is well correlated with true infection.

The logic is indisputable - influenza causes illness in many health care workers each year; the influenza vaccine is a worthwhile intervention to prevent an individual from getting influenza; healthy adults respond better to vaccine than the elderly and those with chronic medical conditions (the very persons who make up most of the hospitalized and long-term care patients); a person who doesn't get influenza won't spread it, and someone who does get influenza has a very good chance of spreading it to others; a significant proportion of health care workers are infected annually and many continue to work while ill; health care workers can spread influenza to vulnerable patients; influenza immunization of health care workers will reduce that risk.

Dr. Jefferson reveals his own biases in the last paragraph of his letter whereby he suggests the BC health care worker influenza policy is the practice of "tyrants."  Internationally recognized ethicists would disagree, including Arthur Caplan of the Center for Bioethics at the University of Pennsylvania, who has stated that "Health-care workers have an absolute duty to do what can be done to ensure they do not transmit disease to those at grave risk who cannot protect themselves."

The great majority of public health and influenza experts across North America and the UK are convinced that the weight of evidence favours the protective effect of influenza vaccines. Far from being a "tyrannical" notion, professional bodies from every healthcare discipline have gone on record as stating that patient protection through influenza vaccination is part of a "duty of care". These groups include NACI, the US Advisory Committee on Immunization Practice, The Society for Healthcare Epidemiology of America, The Healthcare Infection Control Practices Advisory Committee, the US National Patient Safety Foundation, The American Hospital Association, The American Academy of Family Medicine, The American Academy of Pediatrics, and the American College of Physicians.

Significant professional associations in Canada and B.C. strongly support annual influenza immunization of health care workers, including the Canadian Nurses Association, the College of Registered Nurses of B.C., the BC College of Physicians and Surgeons, the BC Centre for Disease Control and the U.S. Centre for Disease Control.

It would be a great shame if a lack of evidence that meets the Cochrane Collaboration's narrow evidentiary standard were to be interpreted as evidence of lack of effectiveness of influenza vaccination. In effect- the perfect would then have become the enemy of the good.

Dr. Paul van Buynder, Chief Medical Health Officer, Fraser Health Authority
Dr. Patty Daly, CMHO, Vancouver Coastal Health Authority
Dr. Ronald Chapman, CMHO, Northern Health Authority
Dr. Andrew Larder, CMHO, Interior Health Authority
Dr. Richard Stanwick, CMHO, Vancouver Island Health Authority
Dr. Bonnie Henry, Head of Epidemiology Services, BCCDC
Dr. Eric Young, Deputy Provincial Health Officer
Dr. Perry Kendall, Provincial Health Officer