Newly identified risk factors add to the growing evidence of a causal association between Zika virus and Guillain-Barré Syndrome (GBS), according to a case-control study.
In a study conducted in Puerto Rico, GBS diagnosis was confirmed in 39 of 47 (83%) patients with clinical suspicion of the syndrome from nine hospitals from April 2016 to December 2016. They were compared with 78 control patients to identify GBS risk factors. Three risk factors were identified, Emilio Dirlikov, PhD, of the division of scientific education and professional development for the Centers for Disease Control and Prevention in San Juan, Puerto Rico, and his coauthors said in a research letter to JAMA (2017;318:1498).
Compared with 22% of controls, 82% of case patients experienced acute illness within 2 months of diagnosis (95% confidence interval, 4.6-35.3), the investigators reported. Case patients also saw higher rates of acute Zika virus infection confirmed by reverse transcription–polymerase chain reaction (23% for case patients vs. 4% for controls; 95% CI, 2.1-120.6) and any laboratory evidence of Zika virus infection (69% for case patients vs. 24% for controls; 95% CI, 4.9-262.5).
“During Zika virus outbreaks, clinical suspicion should be elevated to improve GBS patient prognosis through prompt diagnosis and treatment,” Dr. Dirlikov and his coauthors wrote. This was a small study. “The pathophysiology of Zika virus infection and risk factors for developing GBS require further investigation. Clinical trials of the Zika virus vaccine should monitor for GBS,” they said.
The study was supported with a grant from the National Institutes of Health. Carlos A. Luciano, MD, also reported grant funding from the University of Puerto Rico Medical Sciences, San Juan. No other authors reported any financial disclosures.