Cholera outbreak. Cholera vaccines. Cholera symptoms, history of cholera.

How cholera vaccines are used to respond to outbreaks

Over the last two years, countries’ ministries of health and organisations like Doctors Without Borders (MSF) have been trying to respond to a string of cholera outbreaks around the world. Why are we seeing so many outbreaks? What’s causing them? And do we have the tools and resources needed to respond to them? MSF’s International Medical Coordinator, Dr Daniela Garone, explains in this interview.

What’s the current situation with cholera, and how did things get so bad?

Currently, 16 countries around the world have declared an active cholera outbreak, with many countries reporting larger and prolonged outbreaks. MSF teams are responding to cholera in some of these countries, including Zambia, Zimbabwe, Ethiopia, the Democratic Republic of Congo and Mozambique. Early data shows the number of cholera cases in 2023 rose by 40 per cent over 2022, and deaths increased by over 80 per cent. Over 735,000 cases were reported last year across 30 countries. Just in January this year, nearly 41,000 cases and 775 deaths have been reported.

MSF, Doctors Without Borders, Cholera response in Zimbabwe

Cholera response in Zimbabwe | Mini documentary

In Zimbabwe, 501 people have died from cholera since February 2023. 2,223 people have been infected with cholera in the Buhera district.

MSF has responded to many cholera outbreaks over the last 50 years. Cholera is an extremely virulent disease transmitted through the ingestion of contaminated food or water. While the triggers for cholera outbreaks like poverty and conflict are enduring, today we face a growing threat from climate change, with increased droughts – which can force people to use unsafe sources of water – and floods, which can spread the cholera bacteria. We also see a lack of maintenance of water, sewage and waste management infrastructure due to deteriorating economies, lingering political crises, wars or conflict, or increased movements of people, such as those who are displaced or refugees. A combination of these factors has driven cholera in the countries where we’re responding to outbreaks.

How can we respond to cholera?

First, it’s important to highlight that cholera is a preventable disease. Good access to clean water, proper sanitation infrastructure, and hygiene measures reduce the likelihood of cholera outbreaks. Oral cholera vaccines can also be used to prevent and respond to outbreaks.

MSF, Doctors Without Borders, Niger, Cholera

How MSF responds to a cholera outbreak (CTC).

Unfortunately, for the last two years, the demand for oral cholera vaccines has exceeded up to four times the global production capacity. Limited manufacturing capacity has meant that only so many doses are being made. And with the extraordinary number of outbreaks around the world, the increased demand for the vaccine has far outstripped supply.

Measures have been put in place to try to maximize the limited availability of cholera vaccines. In October 2022, the International Coordinating Group (ICG) on Vaccine Provision1 – of which MSF is a member – made a last-resort decision to temporarily reduce the number of cholera vaccine doses given to people from the recommended two doses to one, to stretch out supplies. With two doses, immunity against infection lasts for three years. A single dose will provide some protection, and that’s why we are using this approach, but it is unclear how long immunity will last.

Image of a Cholera Treatment Center in Quelimane Mozambique
At the Cholera Treatment Centre of Quelimane, in Zambezia Province, MSF installed decorations to make the paediatric ward more child friendly. Date taken: 01/04/2023.
Martim Gray Pereira/MSF

What’s the situation with the oral cholera vaccines today?

Unfortunately, nearly 18 months since the ICG suspended the two-dose strategy for outbreak control, the situation has worsened. Today, only one manufacturer makes the pre-qualified version of the vaccine2 and is producing at their maximum current capacity after another manufacturer left the market at the end of 2022.

Even the one-dose strategy has not been enough. In 2023, 76 million doses were requested by 14 countries to implement a one-dose strategy, but only 38 million doses were available. If a two-dose strategy had been implemented, the gap in the number of cholera vaccines would be as high as 104 million doses. And this is for outbreak response; it’s not even counting the doses needed for preventive campaigns.

Doses are being manufactured each month – but all the doses in production until mid-March have already been allocated, so the stockpile is currently empty. And unfortunately, there is no short-term solution to increase vaccine production.


Cholera crisis in Southern Africa

"Most of Southern African countries where MSF operates - namely Malawi, Zimbabwe, Mozambique and South Africa, experienced worrying cholera outbreaks in 2023. With climate change increasing, the risk of cyclones and floods and an ongoing shortage of cholera vaccines, the outlooks aren't very good for a disease that is easy to prevent and easy to treat," - Strategic Medical Advisor for Southern Africa, Dr Mounia Amrani, explains what needs to be done to stop cholera in Southern Africa.

With a limited number of cholera vaccines, what else can countries and MSF teams do?

Cholera is preventable and treatable. While vaccines are a critical tool, they are not the only tool we have. There needs to be good access to clean water and sanitation infrastructure such as toilets and waste disposal. They need to be adequate to the size of the community and protected from contamination. Engaging people in communities on hygiene measures, using soap, waste management, how to avoid contamination of water sources, and putting communities in charge of maintaining water points – all of this contributes to more effective outbreak control.

Access to timely testing and laboratory confirmation of cholera is not broadly available in many settings, and this delay in declaring an outbreak can affect an appropriate and timely response. Diagnosis has been happening late in many areas, and cholera is very contagious, so by the time there’s a diagnosis, the bacteria have already been spreading. There needs to be more efforts in wider and earlier diagnosis of the first signs of cholera symptoms.

Cholera outbreak in Zambia. Cholera symptoms, history of cholera.
In the Massala health zone, which accounts for more than 50% of cholera cases in the Ndola district, we are working simultaneously on several fronts: support for the establishment of a patient isolation and treatment unit, specific triage at the health centre level and collaboration with epidemiological surveillance services and community stakeholders. 
Carla Melki/MSF

Although cholera can kill within hours if left untreated, treatment is simple, and nobody should die of cholera in 2024. Treatment requires rehydration, including simple oral rehydration and a course of antibiotics for people with more severe cases. But the hard reality is that many people don’t have timely access to those. Quickly implementing sufficient oral rehydration points in multiple parts of an affected community – ensuring wide access to them – and scaling them up as needed is crucial.

MSF has been responding to cholera outbreaks for the best part of 50 years – we know this saves lives very quickly. Setting up a cholera treatment centre – whether it’s in an existing structure or in tents – is possible within 24 hours.

So, in summary, in addition to vaccination, our focus to prevent and respond to cholera outbreaks must first be on access to clean water and sanitation, improved disease surveillance, better communication and engagement with communities, and improved access to healthcare for those who are sick.