Before revision: Recent experiments where ferrets were exposed to two influenza strains within a short time have provided insight into the timing and contribution of each immune component to cross-protection. While mathematical models which capture the novel observations have been developed and analysed, they have many parameters and it is unclear whether the contributions of each immune component to cross-protection can be recovered from the data .
After revision: Recent experiments where ferrets were exposed to two influenza strains within a short period of time have shown how the effects of cross-immunity vary with the time between exposures and the specific strains used. On the other hand, studies of the workings of different arms of the immune response, and their relative importance, typically use experiments involving a single infection. However, inferring the relative importance of different immune components from this type of data is challenging. Using simulations and mathematical modelling, here we investigate whether the sequential infection experiment design can be used not only to determine immune components contributing to cross-protection can be recovered from the data .