Table 2.

Summary of the assumptions of the antibody response model and in the model of virus circulation. Alternative assumptions are tested in additional sensitivity analysis. VNT: Virus neutralization titer.

Submodel	Baseline assumptions	Alternative assumptions
Antibody response model	• Infection with a virus increases the VNT of the virus (direct response model) according to a zero-truncated Poisson distribution • Infection with a virus increases the VNT of the other virus (cross-reactivity model) with a zero-truncated Poisson distribution • Independence of the homologous and cross-reactive responses • Only a fraction of infections lead to a cross-reactive response	• Different distributions of the response model (zero-truncated negative binomial) • Cross-reactive response is proportional to the infecting virus antibody titer boost
Risk of infection	• No circulation of ONNV in Martinique • No other virus with potential for cross-reactive response circulates • CHIKV and ONNV outbreaks occurred in the recent years	• The annual probability of infection by CHIKV and ONNV is constant (model of endemic circulation) • No CHIKV in Mali