Inactivated parenteral influenza vaccine probably leads to lower influenza assessed by laboratory confirmation Timing of assessment:… compared with placebo or 'do nothing' (moderate certainty).
Inactivated parenteral influenza vaccine probably leads to lower influenza‐like illness assessed by subjective report Timing of… compared with placebo or 'do nothing' (moderate certainty).
Influenza vaccine may leads to lower influenza compared with placebo (low certainty).
Influenza vaccine probably leads to lower influenza‐like illness compared with placebo (moderate certainty).
Inactivated influenza vaccine probably leads to lower influenza‐like illness assessed by subjective report compared with placebo or do nothing (moderate certainty).
Inactivated influenza vaccine leads to lower influenza assessed by laboratory confirmation compared with placebo or do nothing (high certainty).
Live attenuated influenza vaccine probably leads to lower influenza assessed by laboratory confirmation compared with placebo or do nothing (moderate certainty).
Live attenuated influenza vaccine may leads to lower influenza‐like illness assessed by subjective report compared with placebo or do nothing (low certainty).
Inactivated parenteral influenza vaccine showed no clear difference in hospitalisations Timing of assessment: single influenza season compared with placebo or 'do nothing' (low certainty).
Inactivated parenteral influenza vaccine leads to higher fever assessed by subjective report Timing of assessment: single… compared with placebo or 'do nothing' (high certainty).
Inactivated parenteral influenza vaccine showed no clear difference in nausea or vomiting assessed by subjective report Timing of… compared with placebo or 'do nothing' (low certainty).
The review found no eligible studies for this question.
It is very uncertain whether influenza vaccine changes all deaths compared with placebo (very low certainty).
Influenza vaccine showed no clear difference in fever compared with placebo (moderate certainty).
Influenza vaccine showed no clear difference in nausea compared with placebo (low certainty).
Influenza vaccine showed no clear difference in at least 1 episode of acute otitis media compared with control (low certainty).
Influenza vaccine probably leads to lower courses of antibiotics compared with control (moderate certainty).
Influenza vaccine may leads to higher fever compared with control (low certainty).