Effectiveness of Pandemic and Seasonal Vaccines against A(H1N1) Influenza in France
Author Information
Author(s): Pelat Camille, Falchi Alessandra, Carrat Fabrice, Mosnier Anne, Bonmarin Isabelle, Turbelin Clément, Vaux Sophie, van der Werf Sylvie, Cohen Jean Marie, Lina Bruno, Blanchon Thierry, Hanslik Thomas
Primary Institution: UPMC Université Paris 06, UMRS 707, Paris, France
Hypothesis
How effective were the pandemic and seasonal vaccines in preventing influenza-like illness during the 2009 A(H1N1) pandemic in France?
Conclusion
Pandemic vaccines were highly effective against confirmed A(H1N1) influenza but less effective against influenza-like illness.
Supporting Evidence
- Pandemic vaccines had an effectiveness of 86% against confirmed A(H1N1) influenza.
- The effectiveness of seasonal vaccines was 61% against influenza-like illness during the pandemic.
- Effectiveness estimates were adjusted for age and time.
- Only 2% of ILI cases were vaccinated during the pandemic.
- Vaccine effectiveness was significantly lower against influenza-like illness compared to confirmed cases.
Takeaway
The study looked at how well vaccines worked to stop people from getting sick during the flu pandemic, finding that the pandemic vaccine worked really well for confirmed cases but not as well for general flu-like symptoms.
Methodology
Vaccine effectiveness was estimated using surveillance data from general practitioners and adjusted for age and time.
Potential Biases
Potential biases include selection bias from using observational data and the non-specific nature of influenza-like illness as an endpoint.
Limitations
The study may have selection biases due to the use of non-specific endpoints and observational data.
Participant Demographics
Participants included individuals aged 6 months and older, with a focus on various age groups during the pandemic.
Statistical Information
P-Value
p<0.05
Confidence Interval
30–69
Statistical Significance
p<0.05
Digital Object Identifier (DOI)
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