title: Influenza vaccination in HIV-infected individuals: systematic review and assessment of quality of evidence related to vaccine efficacy, effectiveness and safety.
abstract: BACKGROUND
  Influenza infection in HIV-infected individuals is associated with increased severity of illness. We performed a systematic review of the available evidence on efficacy, effectiveness and safety of seasonal influenza vaccination in HIV-infected individuals.
  
  
  METHODS
  Systematic review, meta-analysis and assessment of evidence quality.
  
  
  METHODS
  Using a previous systematic review as starting point, we searched MEDLINE, EMBASE and Cochrane data base for studies on efficacy, effectiveness or safety of trivalent inactivated influenza vaccines (TIV) in HIV-infected individuals. Evidence quality was assessed for each outcome using the GRADE methodology.
  
  
  RESULTS
  Three randomized-controlled trials and three cohort studies were identified, including a total of 1562 HIV-infected individuals. In adults, TIV prevented laboratory-confirmed influenza with a pooled efficacy of 85% (95% CI, 22-97%) (evidence quality: moderate), but no significant effects on other clinical outcomes were observed (evidence quality: moderate to low). One cohort study showed an effectiveness of 71% (95% CI, 44-85%) for prevention of laboratory-confirmed influenza, whereas no effect on influenza-like illness was found. However, risk of bias was high in all observational studies. In children aged 6-59 months, efficacy of TIV in preventing laboratory-confirmed influenza was 11% (95% CI, -30 to 54%) (evidence quality: moderate). Regarding other endpoints, no statistically significant effects were reported (evidence quality: moderate to low). No severe adverse events following influenza vaccination were observed in these studies.
  
  
  CONCLUSIONS
  This systematic review indicates that TIV is effective in preventing influenza infection in HIV-infected adults but not in young children. For both age-groups, only limited evidence exists for other outcomes, indicating a need for further studies.
authors.affiliation: Immunization Unit, Robert Koch Institute, Berlin, Germany. Electronic address: RemschmidtC@rki.de.
authors.forename: Cornelius
authors.initials: C
authors.lastname: Remschmidt
authors.affiliation: Immunization Unit, Robert Koch Institute, Berlin, Germany.
authors.forename: Ole
authors.initials: O
authors.lastname: Wichmann
authors.affiliation: Immunization Unit, Robert Koch Institute, Berlin, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Harder
mesh_terms: D000328:Adult; D000368:Aged; D015982:Bias; D002675:Child, Preschool; D015658:HIV Infections / Q000276:immunology*; D006801:Humans; D007223:Infant; D007252:Influenza Vaccines / Q000009:adverse effects / Q000627:therapeutic use*; D007251:Influenza, Human / Q000517:prevention & control*; D008875:Middle Aged; D064887:Observational Studies as Topic; D016032:Randomized Controlled Trials as Topic; D015164:Vaccines, Inactivated / Q000009:adverse effects / Q000627:therapeutic use; D055815:Young Adult
chemical_list: D007252:Influenza Vaccines; D015164:Vaccines, Inactivated
keywords: Efficacy and effectiveness; Evidence quality; HIV; Influenza; Systematic review; Vaccine