Influenza.
BACKGROUND
During the autumn-winter months (influenza seasons), influenza circulates more frequently, causing a greater proportion of influenza-like illness and sometimes serious seasonal epidemics. The incidence of symptoms related to influenza as well as influenza-like illness depends on the underlying immunity of the population.


METHODS
We conducted a systematic review and aimed to answer the following clinical question: What are the effects of vaccines to prevent influenza? We searched: Medline, Embase, The Cochrane Library, and other important databases up to March 2011 (Clinical Evidence reviews are updated periodically; please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA).


RESULTS
We found 9 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions.


CONCLUSIONS
In this systematic review we present information relating to the effectiveness and safety of the following interventions: vaccines in adults, children, and older people.
National Agency for the Regional Health Services, Rome, Italy.
Eliana
E
Ferroni
Tom
T
Jefferson
D000208:Acute Disease; D006801:Humans; D015994:Incidence; D007252:Influenza Vaccines / Q000276:immunology; D007251:Influenza, Human / Q000453:epidemiology; D012621:Seasons
D007252:Influenza Vaccines