Zika Virus Infection in the Elderly: Possible Relationship with Guillain-Barré Syndrome

The Zika virus (ZIKV) outbreak in French Polynesia, in 2013, and in Brazil, in 2015, was correlated with neurological complications, which comprised, among others, congenital microcephaly and Guillain-Barré syndrome (GBS), which includes a group of acute autoimmune neuropathies generally reported after respiratory or gastrointestinal infectious diseases. Despite being relatively rare, the incidence rate of GBS rises with age, which makes GBS more frequent in the elderly, in whom it is also a more severe disease with slower recovery than in younger patients. Different forms of GBS have been described having diagnostic confirmation of a previous infection with the ZIKV virus. Although we do not have enough evidence that elderly people are a particularly susceptible population to developing GBS following ZIKV infection, this is plausible. We should consider this possibility, particularly taking into account that aging subjects are more susceptible to infections. In this context, a deeper understanding of how the immune system in the elderly functions in relation to ZIKV infection is necessary, as well as an understanding of what kind of alterations of the nervous system such an infection triggers in the elderly, beyond GBS. This will be relevant for better therapeutic interventions and for designing vaccine candidates that can be applied in an aging population, particularly those prone to develop ZIKV-induced autoimmunity.