Beviserne på effekten af vaccination mod influenza blandt voksne over 65 år er dårlig.<ref name=Ost2012>{{cite journal|last1=Osterholm|first1=MT|last2=Kelley|first2=NS|last3=Sommer|first3=A|last4=Belongia|first4=EA|title=Efficacy and effectiveness of influenza vaccines: a systematic review and meta-analysis.|journal=The Lancet. Infectious diseases|date=januar 2012|volume=12|issue=1|pages=36–44|pmid=22032844|doi=10.1016/S1473-3099(11)70295-X}}</ref><ref>{{cite journal|last1=Jefferson|first1=T|author-link1=Tom Jefferson (epidemiologist)|last2=Di Pietrantonj|first2=C|last3=Al-Ansary|first3=LA|last4=Ferroni|first4=E|last5=Thorning|first5=S|last6=Thomas|first6=RE|title=Vaccines for preventing influenza in the elderly|journal=The Cochrane database of systematic reviews|date=17. februar 2010|issue=2|pages=CD004876|pmid=20166072|doi=10.1002/14651858.CD004876.pub3}}</ref> Vaccinationen får antallet af fraværsdage på arbejde til at falde med i gennemsnit 1/2 dag årligt.<ref>{{cite journal|last1=Jefferson|first1=T|last2=Di Pietrantonj|first2=C|last3=Rivetti|first3=A|last4=Bawazeer|first4=GA|last5=Al-Ansary|first5=LA|last6=Ferroni|first6=E|title=Vaccines for preventing influenza in healthy adults.|journal=The Cochrane database of systematic reviews|date=13. marts 2014|volume=3|pages=CD001269|pmid=24623315|doi=10.1002/14651858.CD001269.pub5}}</ref> Vaccination af børn kan beskytte personer i børnenes omgivelser.<ref name=WHO2012/>
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