Oral Cholera Vaccination Campaign, Maban, South Sudan
February 28, 2013
With the agreement of the South Sudan Ministry of Health, between the end of 27 December 2012 and 2 February 2013, MSF ran a comprehensive cholera vaccination campaign in Batil, Doro, Gendrassa and Jamam refugee camps, and also covered the host community in these areas. Staff from GOAL, IOM, Medair, Relief International, Solidarités, and the Ministry of Health supported MSF in this campaign. In total, more than 132,000 people were vaccinated with the requisite two doses of the oral vaccine drops.
The anti-cholera vaccine
The anti-cholera vaccine used is pre-qualified by the World Health Organisation (WHO). It is administered in two doses given two to six week apart. It offers reasonably high protection lasting at least two years and can be administered to all people over one-year-old.In addition to preventing possible cases, some evidence suggest that this vaccine also provides herd immunity with high coverage.
In the past, MSF has used the vaccine as a preventive treatment in endemic countries and during cholera epidemics to limit the spread of the outbreak. This, however, was the first time that MSF had used the vaccine as a preventive measure on such a large scale in such a remote area with such access constraints. It was also the first time MSF had used this vaccine in a refugee camp.
The vaccine is administered in drops which contain de-activated cells of the bacterium Vibrio Cholerae. By introducing the bacteria to the immune system it induces the initial formation of antibodies against cholera. This allows for a much quicker antibody response by the immune system if the person subsequently comes in contact with live cholera bacteria.
The oral vaccine has been assessed in several clinical trials, one of which was a large scale trial in India in 2011. Scientific evidence proves that the vaccine offers good protection to all age groups including children aged between 1 and 4 years old, and the protection did not decrease during the second year of monitoring.
Earlier vaccination campaigns by MSF
In April and May 2012, MSF used this two-dose oral cholera vaccine for the first time in Africa. 31 MSF vaccination teams were deployed to three bases: Boffa, Tougnifily and Koba in Guinea and vaccinated 163,000 people. While the recent South Sudan vaccination was a preventive measure, the campaign in Guinea was in response to an existing outbreak, and used as a tool to help limit the spread of the epidemic.
It is rare for a cholera vaccination of this size to be conducted as a preventive measure, and a first for MSF. Because the refugees in the camps inn Maban County are so particularly vulnerable, this innovative approach was justified, and the Ministry of Health agreed with MSF that this vaccination campaign would be beneficial.
Because of the geographical conditions in Maban County – a flood plain in the rainy season and a baked black cotton soil wasteland in the dry season – and because of the extreme challenges sourcing, treating and distributing enough clean drinking water, the refugees are entirely reliant on external assistance for their survival. The difficulties of organising rapid supply to this remote area further add to the risk of a cholera outbreak here being dramatic.
Normally in such circumstances, efforts by aid organisations to ensure adequate water and sanitation services would constitute the standard cholera-prevention activities. However the clear difficulties achieving basic minimum water, sanitation and hygiene standards have been highlighted by an outbreak of hepatitis E, another disease that can spread via contaminated water. Given these challenges, the clearly present risk, and the particular vulnerability of the refugees, vaccinating against cholera pre-emptively quickly became an appropriate extra tool to try to prevent a cholera outbreak.
Not a miracle solution
Despite the fact that the cholera vaccine represents a new and promising tool in the fight against cholera epidemics and their control, it cannot be used alone. Prevention, sanitation and hygiene activities within communities remain vitally important, as well as the rapid treatment of symptomatic patients, and a particular emphasis must be placed on the access to clean, appropriately treated drinking water. Investing in water and sanitation activities remains by far the best way to control water-borne diseases.
MSF has today proved that vaccination against cholera in a remote and logistically difficult location is possible. Basic training for the teams is feasible, the vaccine is easy for the patients to take, and seems to be well accepted by the communities.
The vaccine needed to be kept in fridges during the build-up to the vaccination. This became a considerable logistical problem because the vaccine is packaged as one dose per vial, making the transport and storing of 290,000 vials in fridges a huge challenge. Bringing nineteen 200-litre fridges and the generators to keep them running to a remote place such as Maban adds a substantial layer of cost and complexity to use of this vaccine. MSF hopes for the future to see development of cholera vaccines that have all the benefits of oral administration and relative thermo-stability, but that are also delivered in multi-dose vials that will reduce the bulk and logistical challenges of using this product.