What we know about the Guillain-Barré syndrome epidemic in Peru

What is Guillain-Barre Syndrome?

Guillain-Barré syndrome (GBS) is very often a rare post-infectious disease in which the immune system attacks the peripheral nervous system, the one that circulates information between the brain and organs.

It is characterized, at first, by unusual sensations (pins and needles, pins and needles, feeling of cold) or lack of sensitivity, as well as a feeling of weakness, fatigue and muscle cramps at rest, recalls the High Authority for Health (HAS). The disease develops rapidly, and its symptoms worsen within days, which can lead to paralysis of the limbs, damage to the chest muscles, and even impaired speech and swallowing ability.

In most cases, patients recover without sequelae within a few weeks. But, “Even under the best healthcare conditions, 3% to 5% of patients die from complications of the disease, such as paralysis of the respiratory muscles, sepsis, pulmonary embolism or cardiac arrest”, summarizes the World Health Organization (WHO).

According to a 2021 report of the rare neuromuscular diseases sector (Filnemus), one of the twenty-three French national coordination structures for rare disease actors, its incidence rate increases with age, rising from 0.6 per 100,000 per year in children to 2 .7 per 100,000 annually among people age 80 and over.

Why is the situation in Peru worrying?

On June 23, the Peruvian health authorities issued a warning due to an abnormally high number of GBS cases. As of July 9, 191 cases have been reported since the beginning of the year and four patients have died. However, this pathology requires very heavy care, “with 20-30% of ICU admissions”says Mahmoud Zureik, professor of epidemiology and public health at the University of Versailles-Saint-Quentin-en-Yvelines. In 2022 the total number of beds in intensive care it was estimated at 1,200 from the Peruvian newspaper The Republic. “There are fears of service saturation”confirms Nicolas Weiss, neurologist at the Pitié-Salpétrière hospital in Paris.

On Sunday, July 9, the Peruvian Ministry of Health said “The national health emergency (…) for ninety days”. A decision that can be both health and political. “One of the reasons is also the fact that the Ministry of Health says they don’t have enough treatments against GBSsays Mr. Weiss. The activation of the state of health emergency could allow them to access treatment or unblock aid from WHO. » Peruvian health authorities have not communicated since then.

What could be the causes of the epidemic?

Most often, this inflammatory disease is a reaction to an infection. “In two-thirds of cases, the onset of Guillain-Barré syndrome is preceded by an acute viral or bacterial infectious episode, particularly respiratory or digestive tract infections, three weeks to a month”specified the French agency for the safety of health products (Afssaps) in a 2009 report. But the precise cause may remain unknown. “Sometimes we don’t know because we haven’t done the big studies, which are quite expensive, with big control groups.”regrets Professor Weiss.

Some diseases are known to trigger it. So of Covid-19 as shown a review of the scientific literature of 2023. Hospitalization for severe Covid even multiplies by eight the risks of developing GBS in case of severe Covid. But this phenomenon remained “very marginal”nuance the neurologist.

Other diseases may be the cause. French researchers have so presented in 2016 the causal link between Zika virus infection, characterized by flu-like symptoms, and the onset of GBS. They had observed an increase in hospitalizations due to this disease at the time of the Zika virus outbreak in French Polynesia in 2013-2014.

In the case of Peru, dengue appears as an ideal suspect. The country is facing its most serious epidemic since June 1990. A situation caused by the passage of cyclone Yaku in spring, whose torrential rains attracted the tiger mosquito, the main vector of the disease. “In time, it could fit perfectly”agrees Professor Zureik. But not everything fits. The epidemiologist notes the surprising geographical extent of current GBS cases, while dengue is localized in the south of the country.

Other avenues are under consideration. In 2019, the Latin American country had already been hit by a historic GBS epidemic. This was caused by a bacteria transmitted through meat, Campylobacter jejunihe established a retrospective study from 2021. But between these different hypotheses, the incomplete communication of the Peruvian health authorities does not allow a decision, regrets Mahmoud Zureik. Dengue, Zika, unidentified virus or bacteria… at this stage, he repeats, “We don’t know anything.” The only certainty: the cause can only be recent, within a maximum of six weeks before the onset of GBS.

Why do some people blame Covid-19 vaccines?

Ever since the large-scale vaccination campaigns against Covid-19, anti-vaccine circles have seen every medical event as a side effect of injections. The Peruvian situation is no exception, the most active figures in this movement, who have been predicting the worst for two years, have established a link between this GBS peak in Peru and vaccination in the country.

Guillain-Barré syndrome is a rare side effect of vaccines, especially flu vaccines. As regards those against Covid-19, the European Pharmacovigilance Risk Assessment Committee (PRAC) has recognized, in September 2022, a link to the AstraZeneca vaccine. However, it remains very rare as it affects fewer than one in 10,000 people, Remember the European Medicines Agency. A study The 2021 Brit believes there is a link “probable” could be established for fifty-six GBS cases out of more than 85 million vaccinations.

In the case of Pfizer’s vaccine, cases of GBS are under observation by the National Medicines Safety Agency from August 2021, but no link has ever been formally established, and the recent scientific literature is quite reassuring. Finally, vaccination with AstraZeneca has been only marginal in Peru, dating back to two years ago: it is difficult to see the cause of an inflammatory reaction there in 2023.