Saturday, October 12, 2013

"What, in Fact, Is the Evidence That Vaccinating Healthcare Workers against Seasonal Influenza Protects Their Patients? A Critical Review" / Int'l J Family Medicine

Israeli doctor Zvi Howard Abramson reviewed the literature on healthcare worker flu vaccinations in 2012 and found the evidence to support vaccinations wanting. Read the whole article or his key points:

(i)There are no studies showing that healthcare workers are at increased risk of influenza and its complications or that the vaccine is more effective in this group.(ii)The evidence base for the claim that vaccinating healthcare workers against influenza protects their patients is heavily flawed and inconclusive at best.(iii)The benefit from vaccinating healthcare workers, if any, may differ according to specifics of the patients, location, and worker.(iv)At present, the decision whether to get vaccinated should, except possibly in extreme situations, be that of the individual healthcare worker, without legal, institutional, or peer coercion.
... To summarize these four randomized controlled trials, the repeated conclusion that staff vaccination has preventive value for elderly patients in nursing homes appears to be the result of major methodological errors and wishful thinking. Even when there appears to be less morbidity and mortality in the intervention hospitals this probably resulted from other factors....
The severely biased conclusions of these articles are the crux of the “proof” presented by authorities supporting HCW vaccination. It is somewhat depressing to see the prejudiced manner in which the literature can be presented, as illustrated by the 2010 CDC advisory committee on immunization practices recommendations on HCW vaccination. The above reviewed flawed studies are presented by this committee as evidence and further support is added by stating: “a review concluded that vaccination of HCP in settings in which patients also were vaccinated provided significant reductions in deaths among elderly patients from all causes and deaths from pneumonia.” This statement does not correctly represent the referenced 2006 review which presented the flawed data from the two studies published at that time but actually concluded, very differently, that “…an incremental benefit of vaccinating health-care workers for elderly people has yet to be proven in well-controlled clinical trials”.
This review was updated in a 2010 Cochrane systematic review* based on all four RCTs, which concluded that “no effect was shown for specific outcomes: laboratory proven influenza, pneumonia, and death from pneumonia. An effect was shown for nonspecific outcomes of ILI (influenza like disease), GP consultation for ILI, and all-cause mortality. These nonspecific outcomes are difficult to interpret because ILI includes many pathogens, and influenza contributes less than ten percent of all-cause mortality in individuals over 60 years of age. The identified studies are at high risk of bias... 
We conclude there is no evidence that vaccinating HCWs prevents influenza in elderly patients in long term care facilities."  
According to Abramson, 
This important and unambiguous conclusion was disregarded by the CDC committee in their recommendations,** published six months later, favoring HCW vaccination."

*  R. E. Thomas, T. Jefferson, and T. J. Lasserson, “Influenza vaccination for healthcare workers who work with the elderly,” Cochrane Database of Systematic Reviews, vol. 2, p. CD005187, 2010. View at Scopus

** CDC, “Prevention and control of influenza with vaccines: recommendations of the Advisory Committee on Immunization Practices (ACIP),” Morbidity and Mortality Weekly Report, no. 59, pp. 1–62, 2010.

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