On the temporal association of outbreaks of Zika virus infection, newborn microcephaly, and Guillain-Barré syndrome

During the last couple of years Zika virus (ZIKV) infection has been considered an international public health emergency, due to possible but yet uncertain links with newborn microcephaly and Guillain-Barré syndrome (GBS). Concerns about these links originated from case reports and surveillance data suggesting an outbreak of ZIKV in Brazil was followed by outbreaks of GBS and microcephaly (1,2). A fundamental component of the public health response has been the implementation of a system for surveillance of ZIKV disease and its complications (3).