Cholera ‘third wave’ threatens Yemen
- Study predicts new cholera outbreak in Yemen, half the population at risk
- Rainy season behind risk of epidemic ‘third wave’
- WHO and UNICEF take precautions, roll out vaccine
According to the study, which was published in The Lancet Global Health earlier this month, if the predictions are correct, millions of people in the war-torn country will be infected with cholera in an epidemic wave expected to be larger in scale than the previous two.
An international team of researchers is behind the findings, with contributions from UNICEF, the London School of Hygiene and Tropical Medicine in the UK, the Johns Hopkins School of Public Health in the United States, the Pasteur Institute in France, Yemen’s Central Public Health Laboratory, the World Health Organization, the medical NGO Médecins Sans Frontières (MSF-Doctors without Borders), and the Yemeni health authorities.
The study identified the first wave of the epidemic as a limited outbreak that occurred between 28 September 2016 and 23 April 2017. After the rainy season, a second wave emerged between 24 April and 2 July 2017, which brought a wider outbreak and a rise in the number of infections and deaths. This was followed by a fall in cases between 3 July and March 12 of this year.
More than half of the country's 30 million people now face a risk of cholera infection in a possible third wave. The disease causes severe watery diarrhoea which, in within hours, can develop into dehydration and hypovolemic shock. About half the patients who catch the disease can lose their lives without appropriate dehydration treatment.
Lorenzo Pizzoli, WHO cholera expert and co-author of the study, told SciDev.Net that the UN agency plans to implement preventive measures. These include ensuring access to safe water, environmental sanitation and health services, and helping treatment centres prepare for any coming epidemic.
‟We launched a vaccination campaign on May 6 targeting around 350,000 people in four districts in the governorate of Aden, which continued until May 10,” said Pizzoli.
The organization has received about 400,000 doses of the vaccine, which are to be used initially in Aden. More will be sought later to cover the rest of Yemen, according to Pizzoli. ‟The vaccine is effective as only one dose of cholera vaccination provides protection for six months, while two doses provide protection for three years,” he confirmed.
“The vaccine is effective as only one dose of cholera vaccination provides protection for six months, while two doses provide protection for three years”
Yemeni consultant Talal Al Qahtani, a microbiological diagnostic consultant, praised the timely vaccination campaign.
‟We have to start with the worst-affected areas to avoid any new severe setbacks,” Al Qahtani said, adding that plans should separate the response to cholera from other infections to avoid duplication in efforts across governorates.
But Abdul Hakim al-Kahlani, spokesman for the Houthi government's Ministry of Public Health and Population, strikes a note of caution, saying that ‟the number of vaccines required for the southern provinces is limited, whereas the number needed for the northern provinces is huge”. The quantity of vaccine available in the global market is also very limited, he adds.
‟The target areas for immunization are Sanaa, Taiz, and Aden because they are the worst affected areas,” the UNICEF Information Office in Yemen said in its response to SciDev.Net. “Our initial plan targets ten districts: five in Sanaa, four in Aden, and one in Taiz, which recorded the highest numbers of suspected infections last year.”
The cumulative figures for the number of suspected cases, beginning with the first outbreak and until this month, as confirmed by the UNICEF office, indicate that ‟1.1 million cases of acute watery diarrhoea were recorded”, including over 2,200 deaths. Almost 30 per cent of the cases were among children under five years of age. ‟72 per cent of [Yemen’s] population live in rural areas and rely on open, unprotected well-water for drinking,” says al-Kahlani. “Due to bad habits, such as defaecation in the open, rains and floods sweep all the dirt to the wells, easily causing widespread cases of diarrhoea.”
The study stressed that a number of reasons raise the risk of cholera outbreaks during the rainy season: using unsafe water sources during the dry season, pollution of water sources during the rainy season, and changes in the water levels of zooplankton and iron which keep cholera bacteria alive.
‟The vaccine is only one component of prevention, and we must invest huge resources in prevention by providing clean drinking water, improving hygiene and sanitation services, and supporting solid waste management, while investing with partners in order to strengthen the weakened health system in Yemen,” UNICEF added, commenting on the current vaccination campaign and its effectiveness in preventing a new outbreak.
This piece was produced by SciDev.Net’s Middle East & North Africa desk.