Meta-analyses of flu vaccine effectiveness/ Cochrane Collaboration

The Cochrane Collaboration, the most respected organization of health professionals to evaluate the evidence behind medical therapies, studied flu vaccine of healthcare workers in 2006 and again in 2010.

In 2006 they concluded:

There is evidence that
vaccinating the elderly has a modest impact on the complications from
influenza. There is also high quality evidence that vaccinating healthy adults
under 60 (which includes healthcare workers) reduces cases of influenza. Both
the elderly in institutions and the healthcare workers who care for them could
be vaccinated for their own protection, but an incremental benefit of
vaccinating healthcare workers for the benefit of the elderly cannot be proven
without better studies.

NO evidence supports the wholesale vaccination of healthcare workers to protect patients. 

In 2010 Cochrane concluded:

vaccination for healthcare workers who work with the elderly


No effect was shown
for specific outcomes: laboratory-proven influenza, pneumonia and death from
pneumonia. An effect was shown for the non-specific outcomes of ILI, GP
consultations for ILI and all-cause mortality in individuals ≥ 60. These
non-specific outcomes are difficult to interpret because ILI includes many
pathogens, and winter influenza contributes < 10% to all-cause mortality in
individuals ≥ 60. The key interest is preventing laboratory-proven influenza in
individuals ≥ 60, pneumonia and deaths from pneumonia, and we cannot draw such

There are no
accurate data on rates of laboratory-proven influenza in healthcare workers.

The three studies
in the first publication of this review and the two new studies we identified
in this update are all at high risk of bias.

The studies found
that vaccinating healthcare workers who look after the elderly in long-term
care facilities did not show any effect on the specific outcomes of interest,
namely laboratory-proven influenza, pneumonia or deaths from pneumonia.
effect was shown for outcomes with a non-specific relationship to influenza,
namely influenza-like illness (which includes many other viruses and bacteria
than influenza), GP consultations for influenza-like illness, hospital
admissions and the overall mortality of the elderly (winter influenza is
responsible for less than 10% of the deaths of individuals over 60 and overall
mortality thus reflects many other causes).

Healthcare workers
have lower rates of influenza vaccination than the elderly and surveys show
that healthcare workers who do not get vaccinated do not perceive themselves at
risk, doubt the efficacy of influenza vaccine, have concerns about side
effects, and some do not perceive their patients to be at risk. This review did
not find information on other interventions that can be used in conjunction with
vaccinating healthcare workers, for example hand washing, face masks, early
detection of laboratory-proven influenza in individuals with influenza-like
illness by using nasal swabs, quarantine of floors and entire long-term care
facilities during outbreaks, avoiding new admissions, prompt use of
anti-virals, and asking healthcare workers with an influenza-like illness not
to present for work.

We conclude that
there is no evidence that only vaccinating healthcare workers prevents
laboratory-proven influenza, pneumonia, and death from pneumonia in elderly
residents in long-term care facilities.
Other interventions such as hand
washing, masks, early detection of influenza with nasal swabs, anti-virals,
quarantine, restricting visitors and asking healthcare workers with an
influenza-like illness not to attend work might protect individuals over 60 in
long-term care facilities and high quality randomised controlled trials testing
combinations of these interventions are needed.

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