Skip to Main Content

The expanding monkeypox outbreak is posing enormous communications challenges for public health authorities keen to keep this animal virus from becoming entrenched as a human pathogen.

Among the most exacting is the need to alert the people currently believed to be at greatest risk — men who have sex with men — without further stigmatizing a group that has too often experienced social opprobrium.


At the same time, health officials have to be careful in how they characterize the risk posed by the virus. This isn’t Covid-19, experts stress. Everyone isn’t going to catch it. On the other hand, it’s not clear transmission can be stopped, Hans Kluge, the director for the World Health Organization’s European regional office, warned Tuesday in a blunt statement on where things stand with this unsettling outbreak.

Maria Van Kerkhove leads the emerging diseases and zoonoses unit in the World Health Organization’s Health Emergencies Program. STAT caught up with her to ask about how worried people ought to be about this outbreak. This transcript of the conversation has been lightly edited for length and clarity.

The public health messaging about this outbreak is acutely challenging for several reasons, but one was well illustrated in the update the WHO published on Sunday. On the one hand, WHO said that the global risk was moderate, but that it could become high if the virus gets embedded in the human population. But then it said the risk to individuals was low. When I put all that into an article my editor went …



Exactly. So I would like to get a sense of how dangerous or not dangerous you think this outbreak is.

What we worry about is the fact that we are seeing different transmission patterns. Something we have never seen before. Clearly, this has been circulating in non-endemic countries for a few months. We don’t know exactly how this began. There’s a lot of work around the genetic sequencing. But as we look to explaining this to a much broader audience, we’re recognizing how little we know about this particular virus. And given that the entire world wants answers to questions immediately … we want to make sure that we’re giving the most appropriate answers to everyone, but then also making sure that we are targeting those who are most at risk, to make sure that they have the right information.

Given mistakes that were made in the beginning of HIV, nobody wants to mess this up. We want to be clear, we want to be accurate, we want to be helpful, and we certainly don’t want to harm.

We believe that, with the current information we see in non-endemic countries, that we could prevent onward spread. This is not the same as Covid. In terms of transmission, it’s really physical close contact when someone is symptomatic. So you hear us using phrases like skin-to-skin, mouth-to-skin, which is different than how we would describe a respiratory disease.

The worry that we have is, number one, we don’t know the extent of infection so far. The latest info we have — around 300 confirmed cases, another hundred suspected cases — that’s not an explosive outbreak like we saw with Covid-19, but it’s definitely different. Across 23 countries — that’s spread quite far. And that indicates to us that there are more cases that are being missed.

It seems to be that most of the cases are in the MSM [men who have sex with men] community. What we have not yet seen is circulation into at-risk populations like pregnant women, vulnerable groups, children. Luckily, so far, we are not seeing severe cases of monkeypox. If the virus spreads into vulnerable populations — people with underlying conditions, children, pregnant women — then we could potentially see a shift in severity and that’s what concerns us.

WHO has raised the specter of it becoming entrenched in human populations outside of the endemic countries of West and Central Africa. And the European Centre for Disease Prevention and Control has mentioned the possibility of reverse zoonosis — the virus moving from people into animal in Europe and gaining a foothold there. If you read between the lines, it looks like you’re all saying: “This could be bad, folks.” Am I overstating that?

No, you’re not.

We’ve learned a lot in the last couple of years about the way that we communicate. First of all, you have to be accurate. Secondly, we have to talk about possibilities. You think of it almost in terms of scenarios. What might happen if we don’t do anything. Or what might happen if does find an animal reservoir, or if it does become entrenched in society. We have to think through that.

It feels like there’s so much we don’t know about this virus. We don’t know the R-naught — how many people, on average, an infected person will infect. Though the transmission rate in a household in Nigeria, say, might not tell you a lot about how much the virus can spread if it gets into networks of men who have sex with a number of male partners.

I think that the behavior of this is quite different. Because we’re seeing spread through social networks, through sexual networks. If you look at the numbers of contacts per case in a household that’s obviously very different than what we’re seeing among the cases that have been detected so far in terms of how many sexual contacts they have had. And in this network sometimes there are anonymous contacts; we don’t always have the names of individuals that need to be followed up.

Our surveillance is biased so far towards MSM communities. We’ve been working with countries to expand that and several countries have expanded surveillance to emergency departments, and ID clinics, to dermatology clinics. But they’re not finding additional cases so far outside of the MSM community.

There have been a couple of health worker infections, but they were men who have sex with men. Based on the discussions that have been had with these cases, it’s far more likely that it’s MSM-related transmission than as a result of their occupation.

There are a number of women among the cases.

There are some women but we’re not seeing it expand like we have within the MSM community.

You mentioned that children appear to be vulnerable to severe disease if they contract monkeypox. Do we know if that’s something intrinsic about being a child, or that knowledge is drawn from a time, closer to the end of smallpox vaccination, when adults had been vaccinated against smallpox, but kids had not?

It’s probably both. There’s very limited information that we have on the epidemiology of monkeypox. And it’s one of the things that needs to be advanced. Who is most vulnerable and why and how is it transmitted? What is the proportion of zoonotic spillover events versus human-to-human transmission? How exactly is transmission happening?

We have some of the basics. But when you get into the detail of it, it’s not good enough. Our understanding of this is not good enough.

Another thing we don’t seem to understand very well is the fatality rate. People talk about between 1% to 10%, depending on the clade of the virus.

We don’t understand mortality rates. The crude mortality rates are based on detected cases. Certainly there have been missed cases, unrecognized cases, which would suggest that the crude case fatality rate is on the high end of what is real. Still, 3% to 6% is not low.

If we look so far at the 300 confirmed cases, we don’t have deaths yet. But we could. We can’t be flippant about it.

I spoke recently to veteran infectious diseases epidemiologist David Heymann, who suggested this outbreak may have been smoldering since before the pandemic but was just recently detected. Do you think that’s a possibility?

One thing I’ve learned during the Covid pandemic is not to speculate. All I can say is in the past, we have had exportations of cases from Nigeria to a number of countries — the U.S., U.K., Singapore, Israel — so it’s conceivable that, once the world opened up after essentially a year and a half of being shut down, there could have been an exportation and there could have been some transmission happening in the MSM community that was unrecognized for quite some time, for sure.

It appears that there have been some amplification events in terms of the social gatherings with sexual networks of MSM. But we haven’t pinpointed it back to one party, one event.

The idea that this could be circulating for weeks or months wouldn’t surprise me just given the numbers that we’ve seen and how many countries we’ve seen report cases.

Part of my concern in covering this is I want to make sure I don’t go overboard and I don’t over-dramatize this.

I think that people are quite cautious about reporting on this, because I get the sense that people think that the world just can’t handle this right now. I think that’s in the backdrop of how all of us are sort of tiptoeing around this.

It’s a terribly unfortunate situation. But we’re going to learn a lot more about monkeypox over the coming weeks and months, wouldn’t you think?

I hope we will.

We have had an issue of circulation, continued zoonotic spillover, likely human-to-human transmission in several countries in Western and Central Africa for several years. Very little attention has been paid to this despite WHO trying to get this on people’s radars and trying to advance attention to it and the need for diagnostics and therapeutics and vaccines.

I really find it so heartbreaking and unfortunate that we need situations like this to push the agenda forward. I think it’s grotesque that we’re only going to be paying attention to this in Africa because it’s affecting non-endemic countries right now. But that’s the sad reality.

Create a display name to comment

This name will appear with your comment

There was an error saving your display name. Please check and try again.