Palais briefing notes on cholera in Yemen and circulating vaccine-derived poliovirus in Syria

from World Health Organization
Published on 09 Jun 2017

Suspected cholera cases in Yemen

Two years of intense conflict have exacted a heavy toll on the country’s health system, as well as on water and sanitation services, and we’re entering the peak season for the spread of diarrhoeal diseases in Yemen. The number of suspected cholera cases in Yemen continues to rise, reaching 101 820 with 791 deaths as of 7 June 2017.

Worst affected are the country’s most vulnerable: children under the age of 15 years account for 46% of cases, and those aged over 60 years represent 33% of fatalities. Cases of the disease have been confirmed in 19 of the country’s 23 governorates WHO and the United Nations Children’s Fund (UNICEF) are honing in on areas reporting the highest number of cases to stop the disease from spreading further.


WHO is in full emergency mode responding to an escalating cholera outbreak in Yemen.
There’s not enough capacity in the country right now to respond effectively. The country’s health system has been nearly destroyed by more than two years of intense conflict.

Less than half of the country’s health centres are fully functional.

Medical supplies are flowing into the country at a third of the rate that they were entering Yemen before March 2015.

Important infrastructure has been damaged by the violence, cutting 14.5 million people off from regular access to clean water and sanitation.

Health and sanitation workers have not received their salaries in more than eight months.

Combination of cholera and malnutrition is also a serious issue.

Health and water and sanitation intervention:

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 (soaps and washing powders).

The current case fatality ratio nationally is less than 1%, however there are pockets with higher case fatality rates such as Ibb, Raymah, Dhamar, Hajjah and Al Mahwit. These ‘hot spots’ are the source of much of the country’s cholera transmission. If we stop cholera in these places, we can slow the spread of the disease and save lives. The Organization is bringing in medical supplies, working to rapidly expand the network of treatment centres and carrying out key prevention activities.

Since 27 April, WHO has provided more than 197 000 bags of intravenous fluids, 410 beds with cleaning supplies, 62 cholera kits (drugs module) and another 17 supplementary cholera kits (renewable supply, equipment, logistics and stationary modules). WHO, in collaboration with partners, has supported the establishment almost 100 diarrhoea treatment centres and 166 oral rehydration therapy corners.

On 25 May, a WHO-chartered Boeing 777 carrying intravenous fluids and cholera kits has successfully landed at Sana’a airport in Yemen. At 67 tons, it constitutes the largest planeload of medical goods WHO has brought into the country since the escalation of the conflict in March 2015. A further 13 tons of supplies have been sent to Aden.

Cholera vaccination?

The use of the oral cholera vaccine (OCV) is just one of the tools available to combat outbreaks.
It is more important to ensure that people can access safe drinking water and effective treatment.
Many aspects should be considered before a vaccination campaign: access to the people and places where the cholera is present, logistical constrains (for example availability of cold chain to store the vaccines safely), availability of the vaccines ( we have a worldwide stockpiles of 2 millions cholera vaccines to respond to many outbreak of choldra in different countries). The stocks should be used in a rational way), trained health workers, enough partners on the ground to conduct the campaign, availability of human and financial resources and social mobilisation activities .


The disease can kill within hours if left untreated. The treatment itself should be simple – oral rehydration solution for mild cases and a combination of antibiotics and IV fluids for severe cases – but in the middle of a conflict, it is not so easy.

More information here:

Circulating vaccine-derived poliovirus confirmed in Syria

A circulating vaccine-derived poliovirus type 2 (cVDPV2) outbreak has been confirmed in the Deir-Ez-Zor Governorate of the Syrian Arab Republic. The virus strain was isolated from two cases of acute flaccid paralysis (AFP), with onset of paralysis on 5 March and 6 May, as well as from a healthy child in the same community.

Outbreak response plans are being finalized, in line with internationally-agreed outbreak response protocols, including plans for targeted vaccination campaigns to rapidly raise population immunity. An initial risk analysis has been conducted, finding low overall population immunity levels in the area but solid levels of disease surveillance. Active searches are being conducted for additional cases of acute flaccid paralysis. Surveillance and immunization activities are also being strengthened in neighbouring countries.

Although access to Deir-Ez-Zor is compromised due to insecurity, the Governorate has been partially reached by several vaccination campaigns against polio and other vaccine-preventable diseases since the beginning of 2016. Most recently, two campaigns have been conducted in March and April 2017 using bivalent oral polio vaccine (OPV). However, only limited coverage was possible through these campaigns. Syria also introduced two doses of inactivated polio vaccine in the infant routine immunization schedule in 2018.

The detection of the cases demonstrates that disease surveillance systems are functional in Syria. The polio programme is working with local authorities and organisations on the ground to respond immediately, using proven strategies. In 2013-2014, Deir-Ez-Zor was the epicentre of a wild poliovirus type 1 (WPV1) outbreak, resulting in 36 cases at the time. This outbreak was successfully stopped; the now-detected cVDPV2 strain is unrelated to the WPV1 outbreak.

Circulating VDPVs are extremely rare forms of poliovirus, mutated from strains in the oral polio vaccine (OPV) that can emerge in under-immunised populations. OPV has been a critical tool in eliminating 99.9% of polio cases worldwide, and while cVDPV is rare, the GPEI is actively working with countries to eradicate both vaccine-derived and wild polio. The same strategies that are eliminating wild poliovirus also stop cVDPV – it remains critical that all countries maintain strong disease surveillance and ensure all children are vaccinated.

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