French Scientists Confirm Link Between Zika Virus and Guillain-Barré Syndrome

Investigators study Polynesian outbreak

French scientists say they have proved a link between Zika virus infection and Guillain-Barré syndrome, a rare disorder in which the body’s immune system attacks part of the nervous system, according to a Reuters report.

In a retrospective study, researchers led by Dr. Arnaud Fontanet of France’s Pasteur Institute analyzed data from a Zika outbreak that occurred in French Polynesia during 2013 and 2014. The investigators calculated the estimated risk of developing Guillain-Barré syndrome at 2.4 for every 10,000 people infected by the Zika virus.

The World Health Organization (WHO) has characterized the current Zika virus outbreak as an international health emergency. The agency’s declaration was largely based on evidence linking Zika virus infection to microcephaly, a birth defect marked by a small head and underdeveloped brain. The WHO is also concerned about rising number of cases of Guillain-Barré syndrome in countries affected by the Zika outbreak. It is not yet clear whether the virus is a direct cause of microcephaly in infants, but experts say the evidence of a link is growing.

The French scientists analyzed data from 42 patients who developed Guillain-Barré syndrome at the time of the French Polynesian epidemic and found that every patient had evidence of a previous infection with Zika virus. Tests also showed that 93% of the patients had been infected within three months of developing the syndrome.

Dr. Jeremy Farrar, an infectious disease specialist and director of the Wellcome Trust global health charity, told Reuters that the study, published in the Lancet, “provides the most compelling evidence to date of a causative link” between Zika virus and Guillain-Barré syndrome.

“The increase in reported cases of Guillain-Barré in Brazil and other South American countries seems to suggest that a similar situation may be occurring in the current outbreak, although the link here is yet to be proven definitively,” he said in an emailed statement.

According to the WHO, approximately 3% to 5% of patients with Guillain-Barré syndrome die from complications, including blood infection, lung clots, cardiac arrest, and paralysis of the muscles that control breathing.

Source: Reuters; February 29, 2016.