Skip to main page content
Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Review
. 2010 Jul 7;(7):CD001269.
doi: 10.1002/14651858.CD001269.pub4.

Vaccines for Preventing Influenza in Healthy Adults

Affiliations
Review

Vaccines for Preventing Influenza in Healthy Adults

Tom Jefferson et al. Cochrane Database Syst Rev. .

Update in

  • Vaccines for preventing influenza in healthy adults.
    Demicheli V, Jefferson T, Al-Ansary LA, Ferroni E, Rivetti A, Di Pietrantonj C. Demicheli V, et al. Cochrane Database Syst Rev. 2014 Mar 13;(3):CD001269. doi: 10.1002/14651858.CD001269.pub5. Cochrane Database Syst Rev. 2014. PMID: 24623315 Updated.

Abstract

Background: Different types of influenza vaccines are currently produced worldwide. Healthy adults are presently targeted mainly in North America.

Objectives: Identify, retrieve and assess all studies evaluating the effects of vaccines against influenza in healthy adults.

Search strategy: We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, 2010, issue 2), MEDLINE (January 1966 to June 2010) and EMBASE (1990 to June 2010).

Selection criteria: Randomised controlled trials (RCTs) or quasi-RCTs comparing influenza vaccines with placebo or no intervention in naturally-occurring influenza in healthy individuals aged 16 to 65 years. We also included comparative studies assessing serious and rare harms.

Data collection and analysis: Two review authors independently assessed trial quality and extracted data.

Main results: We included 50 reports. Forty (59 sub-studies) were clinical trials of over 70,000 people. Eight were comparative non-RCTs and assessed serious harms. Two were reports of harms which could not be introduced in the data analysis. In the relatively uncommon circumstance of vaccine matching the viral circulating strain and high circulation, 4% of unvaccinated people versus 1% of vaccinated people developed influenza symptoms (risk difference (RD) 3%, 95% confidence interval (CI) 2% to 5%). The corresponding figures for poor vaccine matching were 2% and 1% (RD 1, 95% CI 0% to 3%). These differences were not likely to be due to chance. Vaccination had a modest effect on time off work and had no effect on hospital admissions or complication rates. Inactivated vaccines caused local harms and an estimated 1.6 additional cases of Guillain-Barré Syndrome per million vaccinations. The harms evidence base is limited.

Authors' conclusions: Influenza vaccines have a modest effect in reducing influenza symptoms and working days lost. There is no evidence that they affect complications, such as pneumonia, or transmission.WARNING: This review includes 15 out of 36 trials funded by industry (four had no funding declaration). An earlier systematic review of 274 influenza vaccine studies published up to 2007 found industry funded studies were published in more prestigious journals and cited more than other studies independently from methodological quality and size. Studies funded from public sources were significantly less likely to report conclusions favorable to the vaccines. The review showed that reliable evidence on influenza vaccines is thin but there is evidence of widespread manipulation of conclusions and spurious notoriety of the studies. The content and conclusions of this review should be interpreted in light of this finding.

Update of

  • Vaccines for preventing influenza in healthy adults.
    Jefferson TO, Rivetti D, Di Pietrantonj C, Rivetti A, Demicheli V. Jefferson TO, et al. Cochrane Database Syst Rev. 2007 Apr 18;(2):CD001269. doi: 10.1002/14651858.CD001269.pub3. Cochrane Database Syst Rev. 2007. PMID: 17443504 Updated. Review.

Similar articles

  • Vaccines for preventing influenza in healthy adults.
    Demicheli V, Jefferson T, Al-Ansary LA, Ferroni E, Rivetti A, Di Pietrantonj C. Demicheli V, et al. Cochrane Database Syst Rev. 2014 Mar 13;(3):CD001269. doi: 10.1002/14651858.CD001269.pub5. Cochrane Database Syst Rev. 2014. PMID: 24623315 Updated.
  • Vaccines for preventing influenza in healthy adults.
    Demicheli V, Jefferson T, Ferroni E, Rivetti A, Di Pietrantonj C. Demicheli V, et al. Cochrane Database Syst Rev. 2018 Feb 1;2(2):CD001269. doi: 10.1002/14651858.CD001269.pub6. Cochrane Database Syst Rev. 2018. PMID: 29388196 Free PMC article. Review.
  • Vaccines for preventing influenza in healthy children.
    Jefferson T, Rivetti A, Di Pietrantonj C, Demicheli V, Ferroni E. Jefferson T, et al. Cochrane Database Syst Rev. 2012 Aug 15;2012(8):CD004879. doi: 10.1002/14651858.CD004879.pub4. Cochrane Database Syst Rev. 2012. PMID: 22895945 Free PMC article. Updated. Review.
  • Vaccines for preventing influenza in healthy adults.
    Jefferson TO, Rivetti D, Di Pietrantonj C, Rivetti A, Demicheli V. Jefferson TO, et al. Cochrane Database Syst Rev. 2007 Apr 18;(2):CD001269. doi: 10.1002/14651858.CD001269.pub3. Cochrane Database Syst Rev. 2007. PMID: 17443504 Updated. Review.
  • Vaccines for preventing influenza in healthy adults.
    Demicheli V, Rivetti D, Deeks JJ, Jefferson TO. Demicheli V, et al. Cochrane Database Syst Rev. 2004;(3):CD001269. doi: 10.1002/14651858.CD001269.pub2. Cochrane Database Syst Rev. 2004. PMID: 15266445 Updated. Review.
See all similar articles

Cited by 108 articles

See all "Cited by" articles

Substances

LinkOut - more resources

Feedback