Incidence of Guillain-Barré syndrome during the Zika virus outbreak

Dear Editor:

It was with great interest that we read the article “Incidence of Guillain-Barré syndrome at a secondary centre during the 2016 Zika outbreak.”¹ The authors point out that “cases of Guillain-Barré syndrome increased during the Zika outbreak, with an increase in incidence and number of cases per month,” but are unable to establish a direct causal relationship between the 2 conditions. This is a relevant finding. We would like to contribute some ideas and experiences on this subject by comparing the situation in tropical South America, described by del Carpio et al., to that of tropical Southeast Asia, where an outbreak of Zika virus infection was also reported. In this region, the incidence of Guillain-Barré syndrome did not increase during the outbreak.² In fact, Zika virus infection has a broad clinical spectrum³; in tropical Asia, the infection is either asymptomatic or manifests with mild symptoms, with no associated complications.⁴