The ongoing humanitarian crisis in Yemen is one of the most devastating in recent history. Facing civil war and blockades by other nations in the region, the population in Yemen struggles to access food, clean water, and health care. Yemen’s already-battered public health and healthcare system is concurrently battling outbreaks of cholera, meningitis, and diphtheria, likely among others. While Yemen’s outbreaks have not made many major headlines as of late, we wanted to take a few minutes to remind everyone that the country continues to struggle with these massive health emergencies, among a myriad of other challenges.


As of our last look at Yemen—on November 30, 2017WHO’s Eastern Mediterranean Regional Office (EMRO) reported 959,810 suspected and confirmed cases of cholera and 2,219 deaths since the onset of the epidemic. That week saw 13,068 new suspected and confirmed cases reported nationwide, but the epidemic was in its 11th consecutive week of decline. In the most recent cholera response update published by EMRO—February 12-18, 2018—3,362 new cases of cholera were reported nationwide. While thousands of new cholera cases is still daunting, the report offers a sign of hope in that it appears as though the decline in new cases has continued for the 23rd consecutive week. 3,300 cases per week is still far too many, but it is much improved from the peak of more than 50,000 cases in late June 2017. In addition to the nationwide trend, all reporting governorates (analogous to states in the US) exhibited decreasing or stable case counts.

Despite this encouraging progress, the WHO recently warned that Yemen’s upcoming rainy season could could exacerbate the epidemic. A similar story emerged last year as the epidemic exploded. The rainy season, typically June through September, coincided with the peak of Yemen’s cholera epidemic, and expert projections at the time turned out to be considerably less than the 1 million cases reported thus far. If a similar trend occurs this rainy season, it could plunge Yemen even deeper into trouble. Humanitarian access has improved since the Saudi-led blockade of Yemen was implemented in December 2017; however, aid organizations continue to have difficulty accessing the country. If conflict in Yemen continues and adequate aid—food, medical, and otherwise—is unable to enter the country, another major spike in cases during the upcoming rainy season is not out of the realm of possibility.


Our initial Outbreak Thursday report on meningitis in Yemen was published on August 10, 2017. The most current EMRO Weekly Epidemiological Monitor at the time—July 30—reported that 2,146 meningitis cases had been identified from the beginning of 2017 through July 8. A subsequent EMRO Weekly Epi Monitor on August 27 reported 2,467 meningitis cases and 37 deaths through August 6, but information about the outbreak has been sparse since last summer. A recent article published in The Lancet indicates that it is still ongoing but did not provide any associated data.

Interestingly, the July 30 EMRO report mentioned the improved nationwide reporting of meningitis cases as a potential factor in the increased meningitis cases reported in 2017, and the August 27 EMRO report provides a more in-depth look at the elevated meningitis case counts in the context of nationwide reporting efforts.  Compared to previous years—ranging from 2,347 to 2,649 annual cases from 2014-16—the 2,467 cases through August 6, 2017 appears to be significantly higher than expected; however, the number of facilities reporting meningitis cases in Yemen increased from 700 in 2016 to 1,982 in 2017. Now, with nearly 100% of facilities nationwide reporting meningitis cases, it can reasonably be expected to correspond to an increase in the number of cases reported. EMRO reports that the nationwide "attack rate" is lower than what was seen in 2015 and 2016 and actually within the expected “endemic range” for meningitis in Yemen. This is encouraging, but there are likely still surveillance challenges in Yemen that could cloud this analysis. Without knowing exactly how many people are currently in Yemen, it is difficult to discuss or compare “attack rates,” and while nearly all healthcare facilities are now reporting meningitis cases, there are probably additional challenges (eg, adequate diagnostics) that may limit the quality of available surveillance data.


Though the cholera outbreak receives the majority of international attention, diphtheria is also having a devastating impact on children in Yemen.  Yemen's diphtheria outbreak began in August 2018 and was initially reported to the WHO in October. When Outbreak Observatory originally discussed diphtheria in Yemen—November 30, 2017—the outbreak was fewer than 200 cases  (20 deaths). By January the outbreak had grown to 799 cases and 54 deaths, and EMRO added the diphtheria in Yemen to its list of “current public health events of international concern.” The most recent Weekly Epi Monitor—March 11, 2018—reports a total of 1,265 cases of diphtheria in Yemen, including 73 deaths.

According to a February 24, 2018 Yemen Ministry of Public Health & Population (MoPHP) situation report, children represent 20% of probable cases and 36% of deaths. The vaccine strategy outlined in a February 10 situation report aimed to vaccinate 2.7 million children between the ages of 6 weeks and 15 years across 38 priority districts, with the first round of vaccination operations to take place between February 24-29. The February 24 situation report indicates that the first round would take place March 5-10, so it is unclear to what extent the vaccination operations have been conducted. The data provided in the February 10 situation report indicates that children represented 30% of probable cases and 47% of deaths, so it is possible that vaccinations have begun to make an impact in Yemen; however, additional information is required to fully understand the situation on the ground.


The humanitarian crisis in Yemen continues to devastate the population, and inadequate access for international humanitarian aid organizations continues to exacerbate health-related issues. Even if public health and healthcare response are able to bring these outbreaks/epidemics under control, Yemen will remain at elevated risk for these types of events due to the absence of critical public health and healthcare infrastructure, including clinical care, epidemiology and disease surveillance capabilities, and environmental health services. International support will be a key tool for rebuilding and maintaining this capacity during and after the ongoing conflict.


Image courtesy of CIA

Outbreak Observatory aims to collect information on challenges and solutions associated with outbreak response and share it broadly to allow others to learn from these experiences in order to improve global outbreak response capabilities.