A massive cholera epidemic in Yemen has now surpassed 100,000 cases, with some, including the World Health Organization (WHO), predicting that cases could reach as many as 300,000 in the coming months. As of June 8, WHO reported 101,820 cases with 791 deaths, with children (46%) and adults over age 60 (33%) accounting for the majority of cases. However, the full scale of the ongoing crisis is likely underestimated given neglected reporting systems in the war-torn region. This “runaway cholera epidemic,” which began in October 2015, is “killing one person nearly every hour,” and will only continue to grow if a ceasefire between opposing forces is not reached, allowing public health and aid workers to reach affected individuals. In addition, response efforts have been hampered by difficulties in active case finding, the blockage of relief supplies by Saudi-led coalition forces, and the theft of vital goods such as food by “local groups and warlords.” The country’s capital, Sanaa, has been particularly hard-hit by the epidemic, prompting authorities to declare a state of emergency in mid-May.

The cholera epidemic comes amid the “largest single-nation humanitarian crisis in the world.” Yemen’s “Forgotten War” began more than two years ago between the Huthi armed group loyal to former President Ali Abdullah Saleh and a military coalition (members include the United Arab Emirates, Bahrain, Kuwait, Qatar, Jordan and Sudan) led by Saudi Arabia and supported by sitting President Hadi. This war has further “exacerbated an already severe crisis resulting from years of poverty and poor governance causing immense human suffering.” According to Amnesty International, an estimated 18.8 million Yemenis rely on humanitarian assistance, and a partial aerial and naval blockade instituted by coalition forces to prevent supplies from reaching Huthi forces has negatively impacted access to clean water, food, and medical supplies. Additionally, the war has displaced more than three million people from their homes and destroyed the country’s public health and healthcare infrastructure, leaving fewer than 45% of health facilities still functioning, only two in five of which are able to properly diagnose and treat infectious diseases.

Cholera is an acute diarrheal disease that causes between 21,000 and 143,000 deaths worldwide per year. Most cases can be treated with oral rehydration solution (ORS), and clean water and sanitation are paramount to controlling transmission. The destruction of Yemen’s health, water and sanitation systems during the ongoing war have all contributed to the rapid spread of Cholera in Yemen, and the fighting has made it extremely difficult to treat and prevent the disease. According to WHO, in addition to the destruction of Yemen’s water and sanitation facilities, warm weather and heavy rains have washed uncollected waste into the water supply, making conditions for disease spread even worse. Nearly two-thirds of the population does not have access to clean drinking water, and food is scarce, with many suffering from malnutrition.  

Despite the difficulties in responding to a growing infectious disease epidemic in a country plagued by war, the United Nations Children’s Fund (UNICEF), WHO, and their partners have made some positive strides. According to a WHO report, “nearly 3.5 million people across the country have been reached by disinfecting water tanker filling stations, chlorinating drinking water, restoration of water treatment plants, rehabilitation of water supply systems, providing household water treatments, and distributing hygiene kits (soap and washing powders).” Medical supplies have been delivered to Oral Rehydration Centers and Diarrheal Treatment Centers across Yemen, “where patients are being screened and provided immediate medical support.” Additionally, education on hygiene is being disseminated to affected populations. According to WHO, however, funding requirements to continue joint response activities for the next six months will top US$66.7 million. While donations can offset this to some extent, more will be needed, along with additional boots on the ground to access those entrenched in areas of conflict.

As of yet, there has been no mention of whether or not a cholera vaccination campaign will be deployed in the region. While implementation of a large-scale vaccination effort in Yemen would prove challenging, a recent successful nation-wide campaign to vaccinate children against measles and polio reached nearly five million children in Yemen in 2 months. This demonstrates that it may be possible to implement a cholera vaccination campaign, but public health authorities might decide to focus their efforts instead on delivering ORS to the ill as fatalities grow by the day. According to WHO guidance on the use of the Oral Cholera Vaccine (OCV) in humanitarian emergencies, the OCV “should be considered by local health authorities to help prevent the spread of current outbreaks to new areas as an additional control measure, depending on the local infrastructure and capacities, and following a thorough investigation of the current and historical epidemiological situation, and clear identification of geographical areas to be targeted;” however, improving water and sanitation, providing treatment to infected individuals, and mobilizing communities should be the primary control measures.

The largest-ever cholera vaccination campaign was deployed in Haiti in October 2016 after hurricane Matthew damaged water and sanitation systems and led to a surge in cholera cases. More than 729,000 people were successfully vaccinated, despite numerous logistical challenges including the need for cold-chain storage of the vaccine, downed power lines, and damaged roads. However, as noted by Dr. David Sack during the response to the Haiti cholera outbreak, while massive vaccination efforts can keep outbreaks from exploding, the long-term solution for controlling the spread of cholera is access to safe drinking water. In war-torn Yemen, a decision to deploy the vaccine will likely take into account both the failing infrastructure in the region and the dangers inherent to healthcare workers serving in a war zone.