ZAMBIA: New results further demonstrate effectiveness of single dose of oral cholera vaccine

Thursday, February 8, 2018 — In another promising development for people affected by large-scale cholera epidemics, recent data from Zambia’s 2016 cholera epidemic has highlighted that just one dose of oral vaccine provides effective short-term protection against the disease during an outbreak, similar to that of the currently recommended two doses.

The results of the study – conducted by Doctors Without Borders (MSF), the organisation’s research arm, Epicentre, the Zambian Ministry Of Health (MOH), the Pasteur Institute and the World Health Organization (WHO) - are being published in the 8 February edition of The New England Journal of Medicine.

Previous studies have already shown the effectiveness of one oral cholera vaccine dose, however they were conducted in countries that had recently experienced cholera. At the time of the 2016 outbreak, Zambia had not reported a case of cholera in four years.

“According to these results, people vaccinated can be protected against cholera a few days after receiving one dose,” says Dr. Francisco Luquero, Epicentre. “This is important in outbreaks when we need to protect people quickly. We now know that just one dose provides adequate short term protection both for people with recent exposure to the disease and also for those who have not been exposed to it in several years, such as people in Lusaka and much of sub-Saharan Africa.”

The results for children under five however, are still not clear, as there were few occurrences of the disease in children in the 2016 epidemic. “It is important that future studies look at the effect of the vaccine on children under five, as they are generally less protected and more vulnerable to the disease,” continues Luquero.  

In April 2016, the Zambian MOH, supported by MSF and the WHO, implemented an emergency single-dose vaccination campaign in Lusaka. It targeted more than half a million people.  A global shortage of vaccines at the time led to the decision to provide one dose only, therefore allowing more people to be protected.  The second dose was delivered in 2016 by the MOH, when more vaccines became available. 

“While the availability of vaccines has improved in recent years, the number is still far from being sufficient to tackle the large-scale outbreaks we are currently seeing, such as those currently ongoing in the Democratic Republic of Congo, or Yemen.”

“However, we are extremely encouraged by these results which will mean more people can be protected from this potentially deadly disease,” concludes Luquero.   

Cholera is a water-borne disease which causes profuse, watery diarrhoea and vomiting. If left untreated, it can be fatal. The disease is most common in densely populated areas where sanitation is poor and water supplies are not safe.

Women taking a single dose of the oral cholera vaccine at St Joseph Church, one of the 15 sites used by MSF in Kanyama district for a massive vaccination campaign in Lusaka. Photographer: Laurence Hoenig
A group of children who have been vaccinated stand at the exit of St Joseph Church, one of the 15 sites used by MSF in the district of Kanyama during a massive cholera vaccination campaign in Lusaka. Photographer: Laurence Hoenig
Children at the exit of the vaccination centre proudly showing their vaccination certificate<br/>Picture taken at Grace Centre, one of the 15 sites used by MSF in Kanyama district for a massive cholera vaccination campaign in Lusaka. Photographer: Laurence Hoenig
Cholera Vaccination at St Joseph Churh, one of the 15 sites of vaccination in Kanyama districts. Photographer: Laurence Hoenig
MSF, in collaboration with the Ministry of Health and World Health Organization, launched a cholera vaccination campaign after an outbreak was declared in February. The goal is to protect more than 500,000 people against cholera infection. Photographer: Laurence Hoenig
Man taking a single dose of the oral cholera vaccine at St Joseph Church, one of the 15 sites used by MSF in Kanyama district for a massive vaccination campaign in Lusaka. Photographer: Laurence Hoenig
More than forty vaccination sites have been set up in the outskirts of Lusaka. Health promoters and community mobilisers, often volunteers from the neighbourhoods, go from street to streets to telling residents about cholera immunisation campaign and its benefits. Photographer: Laurence Hoenig
Queue in front of True Vine Church, one of the 15 vaccination sites used by MSF in Kanyama district during a massive vaccination campaign against cholera in Lusaka. Photographer: Laurence Hoenig
Self Help Center site, one of the 15 vaccination sites used by MSF in Kanyama district during a massive vaccination campaign against cholera in Lusaka. Photographer: Laurence Hoenig
The 'informal settlement' around True Vine Church, one of the 15 vaccination sites used by MSF in Kanyama district during a massive vaccination campaign against cholera in Lusaka. Photographer: Laurence Hoenig