Skip to content

When you choose to publish with PLOS, your research makes an impact. Make your work accessible to all, without restrictions, and accelerate scientific discovery with options like preprints and published peer review that make your work more Open.

PLOS BLOGS Speaking of Medicine and Health

Cholera in Yemen: Why are vaccines not being used?

PLOS Medicine Specialty Consulting Editor Lorenz von Seidlein urges the WHO to act in response current cholera outbreak in Yemen

According to Oxfam/BBC the current cholera outbreak in Yemen has caused more cases and deaths (in a very short time) than any other cholera outbreak on record. The International Committee of the Red Cross and the UN have pointed to the Saudi-led naval and aerial blockade and bombing campaign as central causes behind the preventable cholera epidemic. From 27th April to 18th July 2017, 362 545 suspected cholera cases and 1,817 deaths (CFR: 0.5%) have been reported in 91% (21/23) of Yemeni governorates and 88% (293/333) of the districts. In comparison, the infamous 2008 outbreak in Zimbabwe had 98,596 cholera cases and 4,369 deaths reported over a 12 month period. The massive outbreak in Haiti, which started in 2010 and continues to this day, has resulted in over 800,665 Haitians reporting with cholera and a death toll of 9,480. Based on these massive failures of public health systems and inadequate responses by the international community it would have been reasonable to expect in Yemen a concerted international intervention including health promotion and vaccine campaigns. Unfortunately, this does not seem to be the case.

Despite the availability of an efficacious vaccine through a global stockpile, it wasn’t until nearly three weeks after the start of this epidemic wave (15th June) that the WHO and Ministry of Health announced that vaccine would be delivered to Yemen, although only 1 million doses, compared to the millions of people at high-risk.  On 10th of July the UN and its daughter-organisation the WHO announced that the Yemen Ministry of Health, in consultation with the WHO had decided to cancel cholera vaccination plans despite 500,000 doses sitting at the airport in Djibouti due to arrive in Yemen that week. WHO spokesperson Tarik Jasarevic made the surprising announcement that vaccines were no longer a priority given the rapidly evolving epidemic and that officials would instead focus on ‘scaling up access to clean water and sanitation, treatment to people affected and working with communities to promote hygiene, sanitation and cholera prevention.’ ‘Experience shows that vaccinating once a cholera outbreak is established in a community has little or no impact on preventing further spread.’ Further, the UN cited concerns that providing the limited vaccine to some areas and not others may cause disputes.

While fighting such a large cholera outbreak in the middle of a conflict is surely complicated, not using all effective and available tools at our disposal to fight the disease is short-sighted. The limited supply of vaccine, equity issues and the myth that cholera vaccinations have no impact once an outbreak has started were also used as an excuse in Haiti not to use vaccine. It is unacceptable that 7 years later, despite evidence showing vaccine can play an important role in protecting people, that there is insufficient supply to cover all those in need. Perhaps if more vaccine was available (the vaccine demand exceeds supply every year since the oral cholera vaccine stockpile has been initiated in 2012), a nation-wide campaign may have been under way as early as last month. Water, sanitation and hygiene interventions alone can’t be relied on when the infrastructure to provide safe water and sanitation is actively being destroyed. Vaccinations can protect the most vulnerable populations until a more permanent solution has been found. In a paper published in PLOS Medicine last year Azman and colleagues showed that “Reactive vaccination campaigns using a single dose of OCV may avert more cases and deaths than a standard two-dose campaign when vaccine supplies are limited, while at the same time reducing logistical complexity.” The paper applies directly to the current situation in Yemen where 500,000 doses could protect 500,000 people.

The responses to the cholera outbreaks in Zimbabwe as well as in Haiti were marked by the poor performance of the WHO, which was absent at best and blocked promising interventions at worst. The incompetent response of PAHO/WHO in Haiti is at least in part to blame for the persistent cholera transmission in Haiti. In response personnel changes have taken place in Geneva and a stockpile for oral cholera vaccines has been established. The results are still disappointing. Serious action is needed in Yemen to minimize the devastating toll on the population. Technical and political leadership from WHO is key in this complex environment. One salient detail of the cholera outbreak in Yemen is Tedros Adhanom who took over as WHO director in July 2017, was born in Asmara, at the time part of Ethiopia now Eritrea a neighbouring country of Yemen so separated by the Red Sea. Dr. Tedros has visited Yemen in July. He has little time left to make the right decisions.


Lorenz von Seidlein has also worked for 20 years on malaria and other issues in global health. Lorenz is currently coordinating a malaria elimination project with the Mahidol Oxford Research unit In Bangkok, Thailand. He receives a stipend from PLOS Medicine for his contributions as a Specialty Consulting Editor.


Featured Image credit: RIBI Image Library, Flickr

  1. Communicating the scientific findings to lay people, the politicians in this case, is becoming increasingly important. While reactive vaccination with one dose has been shown to be effective in an outbreak situation, more data needs to be generated on preemptive use of one dose vaccine in an endemic situtations to tide over the current shortage of vaccines. And lastly, IVI has to find ways to initiate transfer of the OCV technology to more developing country manufacturers to ensure vaccine security in vulnerable populations globally.

Leave a Reply

Your email address will not be published. Required fields are marked *

Add your ORCID here. (e.g. 0000-0002-7299-680X)

Back to top