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Exploring cross-protection between influenza strains by an epidemiological model
Audrey Lavenu1, Alain-Jacques Valleron, Fabrice Carrat
1Institut National de la Santé Et de la Recherche Médicale INSERM Unité 444, Faculté de Médecine Saint-Antoine, 27 rue Chaligny, 75571 Paris Cedex 12, France. alevenu@dgf.uchile.cl
Virus Research
|May 28, 2004
Summary
Cross-protection between influenza strains can explain why temperate countries typically see only one winter illness peak. Even with 50% cross-protection, succeeding peaks are prevented, aligning with surveillance data.
Area of Science:
- Epidemiology
- Virology
- Mathematical Modeling
Background:
- Influenza surveillance in temperate regions consistently reports a single winter illness peak.
- Co-circulation of multiple influenza strains rarely results in two distinct seasonal peaks.
Purpose of the Study:
- To investigate the hypothesis that cross-protection between influenza strains explains the absence of successive winter illness peaks.
- To model the impact of varying levels of cross-protection on influenza epidemic dynamics.
Main Methods:
- A dynamic population model was employed to simulate the spread of two influenza strains within a single season.
- Cross-protection was quantified as the reduced risk of reinfection after prior infection with a different strain.
- Simulations explored scenarios with different emergence time-lags and cross-protection levels.
Main Results:
- A cross-protection level of 50% between two influenza strains was found to be sufficient to prevent the emergence of a second distinct illness peak.
- The model demonstrated that cross-protection significantly influences the overall epidemic curve, favoring a single peak.
Conclusions:
- Cross-protection is a key factor in shaping influenza seasonality in temperate climates.
- The observed pattern of a single annual peak is likely driven by immunological interactions between circulating influenza strains.