Doctor checking vitals of a non-contagious women with Cholera in Al Sab’een Hospital, Yemen
At the Al Sab’een Hospital in Sana'a, Yemen, a doctor checks on a girl suffering from cholera. © UNICEF/Fuad

Cholera is Surging Around the World and Vaccine Supplies Are Running Low

There are a record number of cholera outbreaks around the world today. Consider this data point: in 2022 alone, 29 countries have reported a cholera outbreak. This compares to 20 countries over the previous five years. The outbreaks are distributed across several regions: countries in the Caribbean, Middle East, Africa, and Asia are experiencing cholera outbreaks — some for the first time in decades.

Amidst all these concurrent outbreaks, there is a global shortage of cholera vaccines to the point that public health officials are suspending the the standard two-dose vaccination regimen in favor of just a single dose.

In this episode, we speak with Dr. Louise Ivers, director of the Harvard Global Health Institute, and the Massachusetts General Hospital Center for Global Health about why there is a sudden surge in outbreaks worldwide, where the outbreaks are the worst, and what can be done about this vaccine shortage.

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Transcript lightly edited for clarity

Where are the Current Cholera Outbreaks Happening? 

Dr. Louise Ivers [00:00:00] The geographic diversity to me is just an example of how if we don’t really pay attention to infectious diseases, they can really become global phenomena.

Mark L. Goldberg [00:02:12] In this conversation, Dr. Louise Ivers mentions the cholera outbreak ongoing in Haiti, and if you want a deeper dive into the political, social and security crisis unfolding in Haiti right now, I recommend you listen to my conversation with Jacqueline Charles, reporter from The Miami Herald, which was published just a couple episodes back.

Dr. Louise Ivers [00:02:56] Some of the worst outbreaks are happening on the continent of Africa. There’s also a brand-new outbreak in Haiti. There are outbreaks in the Middle East, in Syria, in Lebanon. All of those are causes for concern at the moment, although to be honest, for many people who are heavily engaged in the disease of cholera, the persistent outbreaks have never really gone away. And so many of us have been very concerned, at least since the end of 2021, as we saw cases going up but those are some of the hotspots that people might be reading about it in the news right now in particular.

Why are the current cholera outbreaks spread out over the world?

Mark L. Goldberg [00:03:32] What does the geographic diversity of these various outbreaks tell you about trends in cholera? I mean, you’re mentioning an outbreak in the Caribbean, an outbreak in Africa, and I know there are outbreaks in South Asia as well. What does the sheer geographic diversity of these outbreaks tell you?

Dr. Louise Ivers [00:03:50] I’m an infectious disease doctor by training, and we often say infections don’t know borders, which sounds a little bit cliche, but it’s true. You know, we see a disease of cholera, which historically was much more contained in the area of India, Bangladesh, which started spreading as a pandemic many, many years ago, and that pandemic has never really actually been stopped. I mean, it’s the seventh pandemic of cholera, but it has been going on for many, many decades. And so, I think the geographic diversity to me is just an example of how if we don’t really pay attention to infectious diseases, they can really become global phenomena and they can be really devastating to people who get sick from them, but also to health systems that have to try to deal with them and to economies where people are sick. And the economics of the country has to try to respond to control and contain the outbreaks.

Why have cholera cases increased since 2021?

Mark L. Goldberg [00:04:51] So you mentioned earlier that there has been a general increase in cholera worldwide since 2021. Why is that?

Dr. Louise Ivers [00:05:02] We don’t really understand all the factors that go into cholera increasing, but there’s certain things that we could put together as part of the issue of cholera increasing. We definitely see that cholera cases are related to climate and extreme weather events, and that is one factor. We also know that you can stop cholera outbreaks. You can prevent people from catching cholera if they have good access to water and sanitation, and those, sadly, are still very, very lacking around the world. We also know that food security and food insecurity is associated with challenging behaviors for people who may not be able to prevent themselves from putting themselves at risk for cholera. So if you put together the kind of climate, environmental factors, the water, sanitation, hygiene factors, food insecurity, and what’s common to many of the areas where we’ve talked about earlier, having cholera outbreaks is a social and political insecurity and instability that puts people on the move, that puts more pressure on water systems, on sanitation systems, on food systems and add all those things together, you have a bad scenario in which cholera can really increase. So those are some of the things that we’re all thinking about which are related to the increase in numbers.

How does the climate crisis lead to more cholera outbreaks?

Mark L. Goldberg [00:06:17] So access to sanitation or lack of access to sanitation seems like a very straightforward reason why there might be a cholera outbreak in any given location. But there are two other reasons you just cited that I’m curious to learn a little bit more about. The first is this link to climate and extreme weather events. Where are you seeing climate and extreme weather events causing or contributing to a cholera outbreak and how does that relationship work?

Dr. Louise Ivers [00:06:48] So I think of that relationship in two streams: One is the environmental factors of how Vibrio cholerae, the bacteria that causes cholera, are a type of bacteria that can exist in the environment. And so, we think about how with warm weather, with moist environments — Vibrios live in aquatic environments — how when you see changes in the temperature of the air and the moisture and the rainfall, how those can cause a proliferation of Vibrio is an important piece. And then I think about the social factors that are associated with climate and extreme weather. So, when you have floods, for example, and water systems are contaminated with flood water or people are on the move because of flooding or of droughts, and those people that are moving to places where there might be already water insecurity, putting more density of people in places where they’re trying to access the water and food systems being scarce. So, I think those are the two kinds of ways of thinking about how climate and weather are really associated, both from a bacteriological perspective and also from a social environmental perspective.

Where in the world is climate contributing to increased cholera cases?

Mark L. Goldberg [00:07:58] Is there a place, a country, a region where you would see this relationship between a warming, a more moist environment and an increase in incidence of cholera? Is there a specific place or country or region you could cite?

Dr. Louise Ivers [00:08:13] Well, I think there’s a lot of research going on to try to understand and to pinpoint in the exact factors associated with the climate and the weather in terms of the environmental perspective. And there’s definitely some modeling studies from the early 2010’s that looked at rainfall patterns, air temperature patterns and the evolution of cholera outbreaks. Sometimes some of the situation is tied up, as I said, in the movement of people. I want to maybe use the example of a recent cholera outbreak in Haiti, where you have a confluence of circumstances that can sometimes make it difficult to pinpoint what exact one circumstance caused the outbreak, if you know what I mean. So, in Haiti, over the last three or four years, there’s been a dramatic increase in the physical insecurity in the country. There is a lot of gang activity that has made it very difficult for people to get out and move around. There has been a lot of protests against the existing government and in the context of this social disruption, there is a blockade of access to fuel. Lack of access to fuel has caused the fact that even the water purification companies have had a hard time doing their job of purifying water. Then the trucks have had a hard time getting into communities to deliver the water. And you add that into the context of what the local community have reported as an incredibly hot summer with a substantial amount of rainfall in the fall. And now we see a cholera outbreak in Haiti started about a month ago, although there had not been any cholera cases reported there for about three years. It can be challenging sometimes to really unpack the very specific issues of which thing exactly caused an outbreak. But more and more researchers are trying to study and understand this and also use more novel scientific techniques like genomic sequencing to understand exactly where the cholera is coming from. Is it coming from the same place and just reemerging from the environment, or is it being reintroduced by people as we have this increasing global society where people are transporting bacteria with them whenever they go to different places? So, it can be a little bit hard to unpack with some specific details.

How does food security relate to cholera outbreaks?

Mark L. Goldberg [00:10:28] So you also mentioned food security as an aggravating reason that a cholera outbreak may occur. What’s the relationship between food security and cholera outbreaks? And again, where are you seeing this relationship manifesting itself around the world today?

Dr. Louise Ivers [00:10:49] So this is an area that I’m personally interested in from a research perspective, and I work in public health programs, and I also undertake some investigations to try to understand how the social determinants of disease actually realize themselves. And what we noticed in our team, again, working in Haiti, was that in houses where there was a very high measure of food insecurity, that there was a higher rate of cholera and a higher risk of death from cholera compared to families that had food secure households. When I’m talking about food security, I’m talking about access and availability to food. So, you could imagine how there are different ways that food insecurity works. One of them is that if you don’t have reliable access to food in your house, you could develop malnutrition and the children could develop malnutrition. When we have malnutrition, the intestine itself becomes incapable of protecting the human from bacteria that it encounters. There’s a breakdown of the barrier, and there is a change in the immunology in the intestine, which can make a person who accidentally swallows a vibrio cholera more likely to develop cholera. So that’s one pathway. The other pathways are around behavior. So, when you are food insecure and you don’t actually know exactly when you’re going to eat next or your attention is really focused specifically on your next meal, you sometimes have to undertake behaviors that you know are not in your best interest, so you might be more likely to eat leftover food that hasn’t been able to be reheated. Or you might have to scavenge for food, or you might have to choose between purifying your water or sending your child to school or making some other risk calculations. So, we find that food insecurity interrupts risk calculations and it modifies behavior in a way that we hypothesize is one of the ways in which food insecurity is also associated with cholera. And then we know also that food insecurity really exerts a mental toll on people. So, seeing that seeking food is one of the most fundamental human needs and desires, the inability to be certain about your food source puts a mental toll and mental stress on people. It’s associated with anxiety and major depression, and this can also interrupt one’s resilience in the face of an outbreak. So, there are many ways in which we see that food insecurity may be associated with cholera. It’s an area of research for my group and my team. But we have seen in a multinational study that we looked at that when food insecurity in nations is high, there is a higher outbreak risk of cholera in those countries as well.

What caused the current cholera outbreak in Lebanon?

Mark L. Goldberg [00:13:36] I wanted to also ask you about the outbreak in Lebanon, which is, I guess, surprising to me because it’s not a place that one typically associates with cholera. There hasn’t been an outbreak there, I think, since like 1993. What accounts for the cholera outbreak in Lebanon and what does the fact that it hasn’t experienced an outbreak in over almost 30 years and is now in the midst of one tell you about the nature of this disease and about its occurrence globally.

Dr. Louise Ivers [00:14:10] I think that all infectious disease outbreaks really highlight or should highlight the fragility of our societies and our health systems. Specifically, as it relates to Lebanon, generally speaking, we find that outbreaks need to have the bacteria introduced or to reemerge. I mean, it sounds simplistic, but either somebody brought the bacteria to the place, or it was silently existing in a way that didn’t reach the radar of our detection systems, our surveillance systems and environmental situation of water, sanitation, movement of people, insecurity caused it to be able to flourish. If you look at North America, Europe, we don’t really have cholera outbreaks, generally speaking. That is because even if one or two people have cholera when they come to the United States or to Europe, they generally have systems in place such that an outbreak doesn’t occur. So, a person might have cholera, but they have access to latrines, to toilets, to sanitation. They are able to wash their hands. The water is purified, the water is clean. So, you have multiple places in which transmission is interrupted. When you have a situation, for example, in Lebanon where there is a fracture in the system or in multiple parts of the system, whether it’s a movement of people, access to sanitation or pressure on sanitation systems, if you have flooding in areas that normally are used to kind of gravity type of sewage, but flooding has caused the sewage and the water systems to interact in some ways. You have a risk now that anyone who has the bacteria is now able to introduce it, especially into the water system and then later into the food system. So, these are the ways in which we see outbreaks occurring in places where they hadn’t either occurred for some time or where they’re starting to reemerge in a large amount, even if they hadn’t been seen like that before.

How does cholera infect people?

Mark L. Goldberg [00:16:12] So can I have you explain to listeners who might not be aware just how cholera infects people, how it sickens people and how it kills people and who it generally kills?

Dr. Louise Ivers [00:16:26] Yeah, so cholera with a small ‘c’ is the name of a constellation of symptoms: nausea, vomiting and profuse watery diarrhea. They can lose ten liters, 20 liters of fluid through diarrhea in a day. It’s very dramatic. You acquire the bacteria through contaminated water or foods in particular. So, this is why we keep in our conversation talking about water and sanitation. You have to have the sanitation separate from the water, and where they come together, you’re at risk of acquiring the bacteria. So, you eat or drink contaminated water or food; the bacteria multiplies in your intestine and it causes an acute secretory diarrhea. So, your body starts secreting, secreting as a result of a toxin. And what we can see happen is even the healthiest adults can go from walking, talking healthy to almost at death or dying within a matter of hours. Very, very, very dramatic illness that occurs very, very quickly and can kill even the healthiest of people. So, it’s not just children who are at risk from cholera. The adults are very much at risk from cholera as well. What happens is that as the bacteria leaves the body, it has become hyper infectious. So, it’s like the body amplifies the infectiousness of the bacteria, and when it’s pooped out in the diarrhea, that diarrhea is highly infectious. So, you really want to be sure that that is not getting back into the water system, is not somehow contaminating food, maybe through people’s hands or other practices, caregivers helping to take care of the sick, and it amplifies outbreaks. So, one person who gets cholera may then inadvertently through their illness, cause the transmission to many, many other people. And if you add this kind of infectious cycle in the human into the social context that we talked about, maybe where there’s very much overcrowding or where people are in displacement camps or refugee camps, where there’s not enough access to soap to wash their hands or clean water to drink or the sanitation gets flooded by heavy rainfall and contaminates the local water system, you can see how you can sometimes get really explosive outbreaks. What we do see is that in some countries where cholera is endemic, meaning that they have regular yearly outbreaks of cholera, adults tend to have had multiple exposures to cholera over their lifetime, so they do develop some degree of immunity to the disease. So, they might still acquire the infection but not be quite as sick. In those circumstances, you do find that it’s often the children who are the sickest because they have had less time to be naturally exposed over the years to circulating cholera in the environments. What we’re seeing in Haiti at the moment in this outbreak is a large portion of the sick are indeed children, and that might be related to the fact that there was such a long outbreak in Haiti from 2010 until 2019, before many older people had had some exposure to the Vibrio at the time of that outbreak. But we’re not really sure why that’s happening in Haiti just now.

How is cholera treated?

Mark L. Goldberg [00:19:45] It is also my understanding that just as cholera is extremely infectious and can really harm people very quickly, there are also a suite of really effective and frankly really inexpensive treatments that could be given like oral rehydration salts and antibiotics that seem to work pretty well, right?

Dr. Louise Ivers [00:20:05] Yes. Cholera is 100% preventable and 100% treatable, so nobody should die of diarrhea. You can find cholera early by detecting the symptoms and treating people with oral rehydration solution. Very, very simple mixture of sugar and salt and water that helps to establish hydration for the person and can really be very dramatic in saving their lives. Antibiotics, for some cases are also very useful. They can shorten the duration of illness, and they can also reduce the number of days of shedding the bacteria so that a person who’s treated with rehydration solution and antibiotics would be less likely to pass on the infection to others. And then it’s also possible to vaccinate against cholera. There is a very low-cost oral cholera vaccine that was developed a couple of decades ago and is very useful in interrupting outbreaks and in protecting people in both the short and the long term.

Is there a vaccine for cholera?

Mark L. Goldberg [00:21:11] And it’s this vaccine that I’d really love to discuss with you, because as we are speaking, there is a global shortage of this vaccine. In normal circumstances when there’s not a shortage of this vaccine, in what circumstances is this vaccine used? I mean, I take it is both a vaccine used to prevent one from getting cholera in places in which cholera may be endemic, but it’s also used in emergency situations. So, could you just paint the vaccine picture for listeners before we get into a conversation about reasons why there is a vaccine shortage right now?

Dr. Louise Ivers [00:21:49] Yes, so there is a cholera vaccine that is available to travelers in Europe and North America, which we won’t talk about too much, because I think we’re more talking about the global pandemic as opposed to a traveler that might feel that they were at risk. And the traveler available vaccine is not available on the global scale. So, people who die from cholera are usually people who are impoverished, displaced, have less access to medical services and health services in the first place. And they are, generally speaking, not considered by pharmaceutical companies likely to make much money. And the reality is that vaccines that are not going to make much money are hard to get to the market because businesses who are functioning with the profit motive don’t see the motive to move forward. Cholera vaccines have been available for some time, but I would say it’s really in the last decade that their use as a public health tool has become more popular. Data, which became available from Haiti and from Guinea and from South Sudan and other countries that used cholera vaccines as part of outbreak response really showed that using oral cholera vaccination, either in a single dose or two doses, was very helpful to stop outbreaks. When that data became more available, it became increasingly popular to use cholera vaccine as part of outbreak response. So, what happens now is that there is a global stockpile of cholera vaccine, and it is managed by a coordinating group that receives requests for emergency use of the vaccine, and then there is another group that receives less urgent but also important requests for the vaccine. And those groups are trying to decide on any given month which country and which region has a good plan put together. Where is the crisis that they should use the vaccine doses that are available and trying to manage a pretty limited supply. I will add that the supply of cholera vaccines for public health use has been limited for quite some time. The limited availability is really coming to a peak at the moment and really obvious at the moment because as we were talking about, the number of cases has been skyrocketing. So, the skyrocketing number of cases and therefore the demand to use the vaccine is going up just at the same time as the availability of the vaccine is beginning to really plateau and go down. But it has been under some pressure in terms of supply and demand for quite some time.

Why is the cholera vaccine being rationed?

Mark L. Goldberg [00:24:32] And basically, we’re at the point now where this coordinating committee you described is rationing vaccines, trying to decide which outbreaks get the vaccines and which don’t.

Dr. Louise Ivers [00:24:43] Yeah, I think they were always rationing because that’s their job, because if the vaccine was more available, that coordination committee would not be necessary. If the vaccine was more available, countries who need it and want it would just buy it. But because the vaccine was already limited, the coordination group and the stockpile was created to help both stabilize demand so manufacturers could make a certain amount and also help to manage the supply by negotiating with the manufacturers and helping to be the interlocutor. But you’re exactly right. Recently, the International Coordinating Group announced that they would limit the number of doses available to a single dose campaign instead of a two-dose campaign. So that full vaccination or fully up to date on your vaccine would be two doses of these vaccines. But they are limiting it to one now due to the extreme pressure on the supply.

How is the cholera vaccine shortage affecting cholera outbreaks around the world?

Mark L. Goldberg [00:25:38] So typically they would recommend two doses now because of supply shortages, they’re recommending just one dose. How is this limitation in cholera vaccine accessibility manifesting itself around the world? What does the shortage look like on the ground in places where cholera is happening?

Dr. Louise Ivers [00:26:01] What it looks like is that in Haiti, for example, where many of the non-governmental partners have been working to put together a proposal for access to some of the vaccine, they’ll be looking at changing their plans. So, they would be looking at a single dose campaign instead of a double dose campaign. What we know about single dose of this vaccine is that it does work in the short term, and it looks like it works up to about 12 months or so after you take the dose. So, it can be very helpful in the outbreak setting, but the duration of protection is short compared to taking two doses. So, if you take two doses, the vaccine works for four years, maybe longer, but one dose is only going to be good for one year. So, you can imagine as a country or region experiencing an outbreak, now you have to a. Communicate with the population why they’re only getting one dose instead of two — will that help your public trust or cause some distrust? Who knows? I would hope people would still be trusting because I know one dose will work but how do you communicate that? But then it also means that countries and regions are going to have to scramble because they know that it’ll be only protected for one year. And really, what we always are hoping cholera vaccination will do is buy time. Nobody, I think, in public health wants to see a situation in which we’re just constantly vaccinating against a disease that actually could be prevented by water and sanitation. No, everybody needs to have access to clean water and sanitation. Until we do that, we are going to live in a very unhealthy world. So, the idea of vaccination is that you would buy time during which you can work on your water and sanitation systems, in which you can drill for wells, and you can build the piping that you need and the water systems that you need. Let’s go back to this question of a single dose versus a double dose: with a single dose we know you’re buying much less time from a public health perspective, and you’re going to be reacting probably again just a year later, whereas two doses would give you a much longer period of time in which to work.

How can the cholera vaccine shortage be remedied?

Mark L. Goldberg [00:28:09] So you mentioned earlier that the key reason there is not sufficient supply of cholera vaccines right now is because pharmaceutical companies don’t see it in their interest to manufacture sufficient supply. Is there a public policy remedy to this?

Dr. Louise Ivers [00:28:28] Personally, I would love to see public biotechnology. For me, as an infectious diseases doctor, and especially one that works, generally speaking, with health systems that are underfunded and under-resourced, we have to try to incentivize public goods, and it can be very hard to do this in the private sector. And that’s understandable if you look at the private sector’s motivations and what they have to report on. I do think it’s very challenging to envision a world in which we’re building off the profit motive around biomedical interventions, but we still need to serve the most impoverished people with the tools of biomedical discovery. For some time, there was only one vaccine producer making this oral cholera vaccine and then a few years ago, a second company came on board in South Korea, and they began manufacturing, I believe, with the understanding that there would be then two manufacturers going forward. The first has now dropped out of producing, so the second is left kind of on its own, doing everything they can to keep up with the demand, but really being under pressure and physically not necessarily having the infrastructure to be able to produce more vaccine. I see the way out of this as really having public investments in the manufacturing of vaccines and supporting vaccine production around the world, including on the continent of Africa, where they currently have to import many of their routine use vaccines. We see this in the COVID 19 pandemic, a lack of ability to produce their own vaccines and the rest of the world really leaving them out and leaving them behind and hoarding. That’s not the case with cholera vaccines, because the quote unquote rich world doesn’t really need the vaccines in the first place. So, they, generally speaking, just haven’t been paying that much attention to them.

Mark L. Goldberg [00:30:25] In the coming weeks or months, are there any data, points or indicators that will suggest to you whether or not on a global level, cholera outbreaks will continue to get worse or whether or not, say, vaccine supply may meet demand and things might get a little better.

Dr. Louise Ivers [00:30:45] I am watching with some concern the current situation, and I’m hopeful that I will see cases stabilize and reduce. I’m hopeful because I know we have all the tools that we need in 2022 to actually contain and control cholera. We have all the knowledge on how to do this. The thing that gives me concern is, will we actually do this? Will we actually control it? Will we contain it? Are we willing to move resources into it to ensure that it happens? And also, how is the COVID 19 pandemic, which we didn’t really discuss, but I think has really interrupted in many ways the health systems and perhaps surveillance and perhaps things have been happening that we haven’t been able to be aware of in the cholera world because attention was focused on COVID 19. So, to answer your specific question about what I am watching, I’m carefully watching the cholera cases in the countries we talked about. I’m very interested in seeing the case fatality rate for cholera, which ideally would be zero but we’re seeing has been creeping up over the last year or two as well and hoping that to see those things stabilize and then reduce. And then I would love to see the pharmaceutical companies change their mind and one in particular, stay on board, keep production, or perhaps other companies that can come on board to help to manufacture the much-needed vaccines while we try to also improve access to water and sanitation for the planet.

Mark L. Goldberg [00:32:25] Dr. Ivers, thank you so much for your time. This is very helpful.

Dr. Louise Ivers [00:32:29] Oh, you’re welcome.

Mark L. Goldberg [00:32:37] Thank you for listening to Global Dispatches. Our show is produced by me, Mark Leon Goldberg, and edited and mixed by Levi Sharp.