Prior to the current Zika outbreak, the largest ever before recorded was in French Polynesia between October 2013 and April 2014. A new case-control study used data from that outbreak to investigate a possible association between the virus and a spike in Guillain-Barré syndrome that occurred at the same time. The findings, published in The Lancet, suggest strong evidence for a connection.
Guillain-Barré is a condition in which the immune system attacks the nervous system, resulting in rapid-onset muscle weakness and sometimes paralysis. Of 42 patients who tested positive for Zika-fighting antibodies, 41 were diagnosed with Guillain-Barré, according to the researchers. The risk for Zika-positive patients developing the syndrome increased as much as 24-fold.
"This is the first study providing evidence for Zika virus infection causing Guillain-Barré syndrome," the authors conclude. "Because Zika virus is spreading rapidly across the Americas, at risk countries need to prepare for adequate intensive care beds capacity to manage patients with Guillain-Barré syndrome."