Nearly 2 years ago, a cholera outbreak was reported in the Yemeni capital of Sana’a. The outbreak has since torn through much of the rest of the country, becoming the largest recorded cholera epidemic in history. As we have discussed previously in Outbreak Thursday, this health crisis has been fueled by a crumbling health system and deadly conflict. Though international attention may have shifted away from the epidemic, cholera continues to sicken thousands per week in Yemen. Outbreak Observatory last revisited this epidemic in March, but in light of a recent warning from the WHO, we would like to call attention once again to the ongoing crisis and note the need for continued vigilance and data reporting.

What is the Current Situation?

The cholera epidemic in Yemen continues to be a substantial health burden for affected populations. The most recent Weekly Epidemiological Bulletin published by the WHO Regional Office for the Eastern Mediterranean (EMRO)—containing data through July 1—reported a cumulative total of 1,115,378 suspected cases and 2,310 deaths, including 2,597 cases and 3 deaths for that week. Other previous reports indicate a similar level of disease incidence. The most recent official data we identified is from EMRO’s Weekly Epidemiological Monitor published on August 12. It only provides cumulative cases (1,121,189) and deaths (2,326), but these values are fairly consistent with what would be expected based on the weekly morbidity and mortality in older reports.

WHO and UN Warnings

On August 3, Dr. Peter Salama, the WHO’s Deputy Director-General of Emergency Preparedness and Response, announced that recent data trends suggested that Yemen may be “on the cusp of the third major wave” of the cholera epidemic. The comments by Dr. Salama indicate that a “steady recent increase” in cases could signal the beginning of another surge. On August 22, the UN reaffirmed the WHO’s warning of a third wave, and UN spokesman Stephane Dujarric stated that more than 385,000 individuals were vaccinated in Yemen in the month of August. Response operations in the country continue, including mass vaccination efforts; however, a recent campaign aiming to vaccinate 500,000 people in 3 of Yemen’s most vulnerable areas fell well short of its goal, reaching just over half that many.

Cause for Concern

Unfortunately, updated official data on the epidemic or information regarding the current situation on the ground in Yemen are hard to come by, making it difficult to evaluate the potential risk. As noted above, the most recent detailed data that we found from the WHO contained case reports through July 1, more than 6 weeks old by now. We did identify official WHO data published on August 12, but this included only cumulative cases and deaths and the date range was not provided for the associated data. EMRO stopped publishing weekly updates on the epidemic on June 7, with only one situation report published since then (July 7). Additionally, the Emergency Operations Centre (EOC) for the Yemeni government/WHO response to the diphtheria and cholera outbreaks published regular Situation Reports, but the most recent one we found was dated April 14. Considering Dr. Salama’s reference to recent upward trends, current official data would be helpful in understanding the situation on the ground.

After some digging, we were able to identify what appears to be a website for the Yemen/WHO EOC. Information provided on the website is limited, but it does contain a Cholera Dashboard with incidence data from recent weeks, among other things. This data shows cholera incidence of approximately 2,000-2,500 cases per week from mid-March through mid-June. Disease incidence began to increase somewhere between May 21 and July 1, growing steadily over the past several weeks to 5,281 cases for the week of August 6-12. The older weekly data and cumulative data (1,144,024 cases and 2,376 through August 18) provided on this site are consistent with official reports, providing some confidence in the accuracy of this dataset. We cannot confirm the recent data against official WHO/EMRO reports, but this database provides at least some insight into the WHO’s and UN’s cause for concern.

Waning Attention

Global media coverage of the epidemic has waned considerably since the 2017 epidemic wave. In early Autumn 2017, many major news sources from around the world tracked the escalation of the epidemic as it rapidly approached 1 million cases. Media reports took many forms, including discussions of the causes and contributing factors, impactful graphics comparing the situation in Yemen to previous cholera outbreaks, and documentaries or podcasts covering a range of relevant topics. Recent media reports, on the other hand, have largely been limited to coverage of the WHO and UN statements. Despite the fact that the epidemic continues to sicken thousands per week, global attention has largely shifted to other topics, including other major health events such as alleged chemical weapons use in the UK, Nipah virus in India, and Ebola in the DRC.

Conclusion

While no longer center stage, Yemen’s nightmarish cholera epidemic is far from over. Although not nearly as serious as it was in 2017—when weekly incidence exceeded 40-50,000 cases—Yemen is still facing several thousand cases and multiple deaths each week due to cholera, nearly a third of which are children. Complacency is a major challenge in these situations, as the current burden pales in comparison to the previous peak, which can give the impression that the epidemic is under control. Continued surveillance, reporting, and attention, however, are necessary to better understand the situation on the ground and implement response activities to end this epidemic and prevent additional waves of infection.

 

Photo: A photomicrograph of a small bowel tissue sample from a cholera victim; courtesy of CDC/ Dr. Gangarosa.

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.