Lozier MJ, et al. - In this work, household-based cluster investigations were used to assess differences in prevalence of symptomatic Zika virus (ZIKV) infection by age and sex. Researchers noticed that neither female sex nor age were associated with increased prevalence of ZIKV infection, however, both of these were associated with symptomatic infection. Findings supported a further investigation to identify a potential mechanism of age- and sex-dependent differences in reporting symptomatic ZIKV infection.