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Flu vaccine does not reduce risk of severe complications

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Italian researchers have discovered that the influenza vaccine does NOT reduce risk of severe complications from influenza viral infections that result in hospital death, influenza or pneumonia admission among the elderly population.

The finding came after Manzoli L. and colleagues from the University G. d'Annunzio of Chieti in Italy examined data from 32,457 elderly people, of whom 66.2 percent received the influenza vaccine.

According to a recent review, almost all flu vaccine trials, with the exception of one out of 49 of said trials, have not compared the incidence of flu in the vaccinated population with that in those unvaccinated.

Rather, subjects who received flu shots in influenza vaccine trials were only tested for antigens which were produced in response to flu vaccine. When a flu vaccine generated certain levels of antigens as defined by researchers, the vaccine maker claimed that the flu vaccine worked to prevent flu.

The authors of the current study said this result is similar in Italy, where the influenza vaccine is routinely administered to the elderly population, but the impact on the relieving of the illness burden has been rarely evaluated because the cost for a conventional cohort study would be too cost ineffective to conduct.

The researchers obtained in Oct 2006 patient information on their immunization status and main outcomes, such as hospitalizations for influenza, and/or pneumonia, through General Practitioners who documented patient information.

They found that the hospitalization rate was low in the sample population; only 7 elderly patients were admitted for influenza and 135 for pneumonia.  

But using either bivariate or multivariate analysis, the researchers found that vaccination did not significantly reduce the risk of in-hospital death, influenza or pneumonia admission.

The study was published in the June 2009 issue of Journal of Preventive Medicine and Hygiene.

Elderly people, young children and people with compromised immune systems such as those who have become infected with HIV or those who have received cancer treatments are believed to be at higher risk of viral infections, such as influenza.

The Centers for Disease Control and Prevention has never said that the flu vaccine will automatically prevent flu in every vaccine recipient. The Agency admits that the efficacy of a flu vaccine depends on the matching of the viruses included in flu vaccine with the circulating strains; because of this, the efficacy is often actually low. But the health agency reports that even if the drug does not prevent flu, it may help relieve symptoms.

A recent Japanese trial has found that taking high doses of vitamin D may help reduce the incidence of flu in school children.  Vitamin D is known to help produce antimicrobial peptides which are involved in innate immunity against viruses and viral diseases.

By David Liu and editing by Rachel Stockton

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