Meta-Analysis of the Immunogenicity and Tolerability of Pandemic Influenza A 2009 (H1N1) Vaccines
2011

Meta-Analysis of H1N1 Vaccine Effectiveness and Safety

Sample size: 16725 publication 10 minutes Evidence: high

Author Information

Author(s): Manzoli Lamberto, De Vito Corrado, Salanti Georgia, D'Addario Maddalena, Villari Paolo, Ioannidis John P.A.

Primary Institution: University “G. d'Annunzio” of Chieti, Italy

Hypothesis

What is the immunogenicity and tolerability of different formulations of the 2009 H1N1 vaccines?

Conclusion

The study found that several one-dose formulations of the H1N1 vaccine might be effective, but two doses may be necessary for children, especially with low-dose non-adjuvanted vaccines.

Supporting Evidence

  • All 2009 H1N1 split/subunit inactivated vaccines were highly immunogenic after two doses.
  • Oil-in-water adjuvanted vaccines were more immunogenic than non-adjuvanted vaccines.
  • Seroconversion rates were >70% in adults and adolescents after one dose.
  • Seroconversion rates were lower in children and the elderly after one dose.
  • The rate of serious vaccine-related adverse events was low (0.013%).
  • Mild to moderate adverse reactions were more frequent for oil-in-water adjuvanted vaccines.

Takeaway

The H1N1 vaccine works well, especially after two doses, but kids might need two shots to be fully protected.

Methodology

The study conducted a meta-analysis of randomized clinical trials to evaluate the immunogenicity and safety of various H1N1 vaccine formulations.

Potential Biases

Potential sponsorship bias due to most trials being funded by vaccine manufacturers.

Limitations

The study was limited by the short follow-up duration and the majority of trials being sponsored by vaccine manufacturers.

Participant Demographics

Included healthy children, adolescents, adults, and the elderly.

Statistical Information

P-Value

p<0.05

Confidence Interval

95% CI

Statistical Significance

p<0.05

Digital Object Identifier (DOI)

10.1371/journal.pone.0024384

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