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In immunocompetent elderly hoi polloi, influenza vaccine might non protect
against pneumonia in influenza seasons than antecedently expected,
according to an article released on August 1, 2008 in The
Lancet.
Influenza is a viral disease that usually occurs in regular seasonal
epidemics. As it is an RNA-virus, chromosomal mutation is frequent, so new
influenza viruses, similar to one another, often challenge the immune
system in each new year. As a result, the flu vaccine is administered
yearly for a predicted correct of strains meant to protect against that
year's mixture.
A common complication of grippe infection in the aged is
pneumonia, and former work has shown a 20-30% decreased risk of
pneumonia complications in vaccinated individuals. However, these
studies were performed in different populations, so observed
differences could have been caused by underlying variety betwixt the
populations. Additional studies should as well incorporate inmate and
outpatient cases of pneumonia, because most of these ar not treated in
the hospital.
To evaluate the true impact of influenza vaccination on
community-acquired pneumonia Dr Michael Jackson, Group Health Center
for Health Studies, Seattle, WA, evaluated the medical records of 65-94
year olds enrolled in Group Health Cooperative during the 2000, 2001,
and 2002 in the grippe seasons and preinfluenza periods. The
researchers verified the diagnosis using the medical records and
test of a chest skiagram report. Age and sexuality matched controls
were arbitrarily selected for each case. Additionally,� medical
records were examined for potential confounders which power make it
seem like there is a correlational statistics when in reality on that point is none, such as
smoking, lung disease, and various frailty indicators.
In total, 1,173 community-acquired pneumonia were examined alongside
2,346 controls. After adjusting for the identified confounding personal effects
and severeness of other diseases in the patients, influenza inoculation
was not associatd with reducting the risk of pneumonia. They authors
say: "These results could mean that influenza infection only if causes a
small balance of the pneumonias in these people, so that reduction
of the risk of grippe infection does not lead to an important
reducing in all-cause pneumonia. Alternatively, these results could
mean that the vaccine is not selfsame effective in reducing the risk of
influenza infection in aged people at risk of pneumonia. These two
possibilities have quite different implications for vaccinum development
and vaccination recommendations; differentiation between them will need
studies with laboratory-confirmed endpoints, such as pneumonia or
unplayful respiratory outcomes after a confirmed grippe infection."
Dr Edward Belongia, Marshfield Clinic Research Foundation, Wisconsin,
and Dr David Shay, Influenza Division, US Centres for Disease Control
and Prevention, Atlanta, GA, USA, contributed an concomitant comment
in which they state promissory note the new nature of this study: "More studies
that use laboratory-confirmed outcomes and align for a broad range of
confounding variables will provide valuable information nigh the
personal effects of antigenic match and other factors that regard vaccine
strength in elderly adults."
Influenza vaccination and risk of community-acquired pneumonia
in immunocompetent elderly people: a population-based, nested
case-control study Michael L Jackson, Jennifer C Nelson, Noel S Weiss, Kathleen M Neuzil,
William Barlow, Lisa A Jackson
Lancet 2008; 372: 398-405
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Written by Anna Sophia McKenney
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