Does Zika virus infection cause Guillain-Barré syndrome?

Does Zika cause Guillain-Barré syndrome (GBS)? The answer to that question is yes. Or no. More like, maybe? The truth is, we don’t know. Nobody does. Not yet, at least. The Brazil Ministry of Health has reported an increasing number of people affected with GBS – as well as rising numbers of babies born with microcephaly – at the same time as a Zika virus outbreak is going on. Casuality or causality? Is there a true cause-and-effect relationship at play or just your run-of-the-mill post hoc fallacy? The U.S. Centers for Disease Control and Prevention is working to establish whether or not Zika and Guillain-Barré syndrome are related.

Guillain-Barré syndrome


GBS is a rare condition in which the body’s immune system attacks the nerve cells.


·         Prickling in the fingers, toes, ankles or wrists.

·         Weakness in the legs that radiates to the upper body.

·         Unsteady gait or inability to walk or climb stairs.

·         Difficulty with eye or facial movements, such as speaking, chewing or swallowing.

·         Severe pain that may feel achy or cramp-like and may worsen at night.

·         Difficulty with bladder control or bowel function.

·         Rapid heart rate.

·         Low or high blood pressure.

·         Difficulty breathing.


Exact cause is unknown.

Risk factors

·         Male gender.

·         Age.

·         Infection with campylobacter.

·         Influenza virus.

·         Epstein-Barr virus.

·         HIV.

·         Mycoplasma pneumonia.

·         Surgery.

·         Hodgkin's lymphoma.


·         Breathing difficulties.

·         Residual numbness.

·         Heart and blood pressure problems.

·         Pain.

·         Bowel and bladder function problems.

·         Blood clots.

·         Pressure sores.

·         Relapse.


·         Spinal tap.

·         Electromyography.

·         Nerve conduction studies.


·         Plasma exchange.

·         Immunoglobulin therapy.


The link – if any – between the Zika virus and GBS and microcephaly is mystifying, to say the least. For example, the absence of microcephaly in Zika-hit countries other than Brazil baffles health officials. “We have 20,000 confirmed cases of Zika,” Colombian Health Minister Alejandro Gaviria told the press outside a meeting of his peers in Montevideo. “Yet we don't have a single confirmed case of microcephaly. If you extrapolate the rates in Brazil to Colombia, we should have tens, even hundreds of cases.” On the other hand, Colombian Deputy Health Minister Fernando Ruiz said there have been 41 recorded cases of Guillain-Barré​ syndrome seemingly associated with Zika infections, and “authorities said last week there are around 255 cases of Guillain-Barré in Venezuela potentially linked to Zika,” Reuters reports.

Additionally, “46 cases of GBS were notified to the Ministry of Health” of El Salvador “from December 2015 to 6 January 2016;” and “On 15 January 2016, (Martinique)public health authorities reported a first case of GBS possibly associated with Zika virus infection,” according to the European Centre for Disease Prevention and Control’s RAPID RISK ASSESSMENT Zika virus disease epidemic: potential association with microcephaly and Guillain-Barré syndrome. The Pan American Health Organization reported the same number of cases in El Salvador – thrice the usually reported cases in a month. CDC's Leonard Peruski also observes a sees a pattern; “a spike in Guillain-Barré cases most notably in El Salvador and Colombia. There have been some sporadic reports in Honduras.” Previously, researchers had seen an increase in Guillain- Barré cases during earlier Zika epidemics in Micronesia and French Polynesia.

Like WHO Director-General Margaret Chan says of the link between Zika, pregnancy, and microcephaly, the link between the mosquito-carried virus and Guillain-Barré syndrome “is strongly suspected, though not yet scientifically proven.” Nevertheless, “the recent cluster of microcephaly cases and other neurological disorders reported in Brazil constitutes an “extraordinary event” and a public health threat,” requiring “a coordinated international response… to improve surveillance, the detection of infections, congenital malformations, and neurological complications, to intensify the control of mosquito populations, and to expedite the development of diagnostic tests and vaccines to protect people at risk.” In other words, it is better to err on the side of caution. As the saying goes, ‘better safe than sorry.’ Therefore, people who live in or travel to countries where there is active transmission of the Zika virus should follow the CDC’s steps to prevent mosquito bites. And failing that, take acetaminophen or paracetamol – but not aspirin or ibuprofen – to relieve fever and pain caused by Zika, among other symptoms.

Related: The Zika virus: Chronicle of a viral outbreak foretold