Explaining rapid reinfections in multiple-wave influenza outbreaks: Tristan da Cunha 1971 epidemic as a case study

Camacho, Anton; Ballesteros, Sébastien; Graham, Andrea L.; Carrat, Fabrice; Ratmann, Oliver; Cazelles, Bernard

Further analyses to distinguish between the Win and AoN mechanisms will require more empirical data on reinfection at the individual level. Unfortunately, the original paper by Mantle & Tyrrell [13] does not provide such information, but surveillance of more recent influenza outbreaks may offer suitable data. For example, three cases of rapid reinfection by the same strain over a short time scale have been reported during the 2009 H1N1 pandemic [7] . We advocate application of state-of-theart virological and immunological methods to samples from such cases. Alternatively, both parameter estimates and immunological support for the Win model indicate that successive infections by the same strain spaced over more than four to six weeks can only be explained by the AoN mechanism. We advocate application of our statistical approach to other multiple-wave datasets that occurred on a longer time scale than that of 1971's epidemic on TdC. It is also possible that ongoing outbreaks may enable tests of our results, and we refer to electronic supplementary material, text S7, for qualitative guidelines for such tests.