As a result of climate change and the increase in conflicts, the number of cholera cases is currently exploding around the world, according to the World Health Organization (WHO). Reported cases more than doubled between 2021 and 2022 to 473,000, then climbed further to more than 700,000 in 2023.

In the French department of Mayotte, located in the Indian Ocean, a 3-year-old child died of cholera on Wednesday May 8. As of May 6, 58 cases have been identified on the island and a vaccination campaign is underway with more than 4,000 people vaccinated to date, according to the Regional Health Agency. This outbreak comes as a major epidemic is underway in the neighboring archipelago of the Comoros, where there have been 98 deaths and more than 4,900 cases since the start of the year.

An infectious disease that can be devastating, cholera is a scourge that is on the rise throughout the world, primarily affecting poor countries and war zones, particularly in Africa: Comoros, Democratic Republic of Congo (DRC), Ethiopia, Mozambique, Somalia, Zambia and Zimbabwe are among the most severely affected countries.

This list – to which we must add Haiti and Syria – shows how this disease is a marker of poverty, instability and armed conflicts. “There is a strong link between the transmission of cholera and inadequate access to drinking water and sanitation facilities,” underlines the WHO. Places at risk of epidemics are typically refugee camps: humanitarian crises, with the displacement of populations and difficulties in accessing drinking water, considerably increase the risks.

Oral vaccines

Another factor: climate change. By increasing the intensity and frequency of floods, cyclones and droughts, it disrupts access to drinking water and “creates an ideal environment for the development of cholera”, according to the WHO. Recent example: cases of cholera in Mozambique increased tenfold after the passage of Cyclone Freddy, which, at the beginning of 2023, deprived some of the inhabitants of drinking water.

An acute diarrheal infection, cholera is caused by the absorption of food or water contaminated by a bacteria, the bacillus Vibrio cholerae (or cholera vibrio). Three-quarters of infected people express no symptoms. But when it does appear, the disease can be formidable in 10 to 20% of cases, with severe diarrhea and vomiting that cause accelerated dehydration. If left untreated, cholera is one of the most rapidly fatal infectious diseases: death can occur within one to three days. Only rapid treatment by infusion, with the administration of rehydration salts and antibiotics, can prevent death.

Several oral vaccines have been developed and are recommended by the WHO for areas where cholera is endemic and during epidemics. But the multiplication of outbreaks has dangerously limited stocks and forced humanitarian organizations to reduce the number of doses administered during vaccination campaigns. In April, the WHO gave the green light to the simplified version of a vaccine, produced by the South Korean group EuBiologics, to accelerate production and replenish global stocks of anticholera serums.