The flu vaccination does not protect the elderly or very young

Each year at this time, 120 million Americans roll up their sleeves for the annual flu vaccine. Since 2010, the U.S. Centers for Disease Control recommends jabs per year for each American more healthy than six months. The aim is to prevent the spread of infection and minimize the risk of potentially dangerous complications such as pneumonia, especially in the elderly and very young children. But science on the efficacy of the vaccine are rare in these vulnerable groups. And while healthy adults have some protection, may not be as strong as they expect.

A widely cited, based on several large meta-analyzes published a decade ago is that of seasonal influenza to reduce the risk of death among middle-aged winter. However, the research behind this claim has been widely discredited. A 2005 study published in the Archives of Internal Medicine indicated that influenza causes only 5 percent of all excess winter deaths in the elderly, which is equivalent to a flu deaths per 1,000 people over time, is impossible to avoid the blow in their half of all deaths in winter. The following year, a study showed that vaccination coverage among the elderly increased in Italy in the 1980s, there was a corresponding decrease in mortality. In another 2006 article, Lisa Jackson, infectious disease epidemiologist at Group Health Research Institute in Seattle, and colleagues showed that although older people vaccinated were 44 percent less likely to die during the flu season and the elderly were not vaccinated, vaccinated were also 61 percent less likely to die before the flu season has begun. "Naturally, we can not expect the vaccine to take effect before which protects against is going on around you," says Lone Simonsen, Research Professor of Global Health at the George Washington University and co-author of the study conducted in 2005 in the Archives of Internal Medicine.

Researchers now attribute these results to a user strangers "healthy." People who are vaccinated often "are the most fragile or [those] whose health has declined dramatically in recent months," says CDC epidemiologist David Shay. People who choose to be vaccinated against influenza, ie already are healthier and less likely to die.

So how the vaccine really help the elderly? In January 2012, Michael Osterholm, an epidemiologist at the University of Minnesota Center for Infectious Disease Research and Policy, and colleagues published a meta-analysis in The Lancet Infectious Diseases that analyzed the results of all randomized controlled trials conducted between 1967 and 2011 on the effects of influenza vaccines. It concluded that there was no clinical trials evaluating the effects of influenza vaccination among traditional elders. The only vaccine shown to protect against infection and death among the elderly, said, vaccination is a live attenuated vaccine that contains a live version inhalable, modified virus that is not approved in the U.S. for adults over 50 years .

The traditional vaccine not work as well in the elderly because of an idea known as immune senescence, which postulates that people age, their immune systems are weakened, causing the poor response to vaccine, particularly inactivated strains. Although the U.S. Food and Drug Administration has approved a vaccine for high dose for the elderly in 2009, which in theory could solve this problem, no study has yet been published on how effective it is. "The higher dose produces a higher level of antibodies, but not really know what is in correlation," Jackson said. A 2010 review published by the Cochrane Collaboration systematic, a nonprofit independent organization that promotes evidence-based medicine, concluded that "until the role of vaccines in preventing influenza in the elderly is clarified, the most comprehensive and effective strategies for the control of acute respiratory infections should be implemented. "