Can monkeypox be treated?

How might it be possible to prevent people from getting the virus in the first place? And manage those who are unfortunate enough to contract it? Here’s Michael Marks, a professor of medicine at the London School of Hygiene & Tropical Medicine, and a consultant in infectious diseases at University College London hospital…

Michael - So the first thing to recognize is that there is a range of how unwell people are. Many, many individuals with mpox will be really very mildly affected and we have seen in previous outbreaks in the UK and elsewhere that probably 90-95 out of 100 people can be managed at home just with what we call supportive care. So that's simple things like analgesia, dressing the wounds, keeping hydrated. And then there will be a smaller proportion of people who become very unwell. And we know that those are individuals who are more likely to, for example, have problems with their immune system such as HIV infection. Or in the current outbreak in DRC, children are more severely affected. Those individuals may need admission to hospital for specialist care. We don't have any drugs that we know definitely work for mpox. There are some drugs that are being tested in studies to see if they can help people get better more quickly or indeed reduce the risk of dying. But those are all experimental treatments at the moment only being studied to see if they are helpful.

Chris - One of those drugs. An announcement was made a week or so ago suggesting that people just did better when they were in a trial in hospital, but the drug didn't make much difference. But some commentators argued that's because they gave the drug too late. If we'd gone in earlier with the drug, it might have made a bigger difference.

Michael - Yeah, so this is a drug called Tecovirimat or TPOXX, that's the name the drug company uses. And you are right that in the study that was recently announced, everyone regardless of whether or not they got the drug or not, seemed to do better than what is being reported overall in the Democratic Republic of Congo. And we often see that effect in studies. Just if you are generally being looked after by a big research team, you get better general care and so outcomes are better. We know that the virus is not in the blood for very long in mpox infection. And so if we think that the way this drug might work is by stopping the virus spreading around your body if it's going to have any effect at all, you probably need to give it very early in the illness before the virus is already spread everywhere. And with the eye of faith or being optimistic, if you look at the study results, people who got the drug within the first seven days of being unwell seemed to do better. So we don't know definitively, but there is probably enough there to say we should be studying the drug in people. But really targeting it at people who have just become unwell before the virus has had a chance to spread all around the body.

Chris - Is that currently the policy or is it literally only available in a research context? We don't have it generally being rolled out in places where there's disease activity? Or is that not the case?

Michael - So because it's not a proven treatment, really this is a therapy that is available in the research setting. It's not a drug that has been shown to be of benefit to all comers. And so really because there's no proven benefit, its use is restricted predominantly to further studies to see why this person benefits from the drug? Why does this person not benefit from the drug? Can we reliably identify people who if we gave them the drug they would do better than if we didn't give them the drug?

Chris - So it's an iron in the fire. It's a possible future avenue but it's not the mainstay yet. So what are we using as the main way to control the infection at the moment?

Michael - You're right. So we don't have any working antivirals yet. So really the main intervention that we have available to us is vaccination. And that is a strategy that is obviously not about treating individuals once they've already developed the illness, but about reducing risk in the first place. And there are effective vaccines that are available which, if given, can significantly reduce your risk of catching mpox. And probably even if you catch mpox despite being vaccinated, reduce your risk of becoming unwell. So they both have a direct effect, you are less likely to catch the virus and they probably protect you from becoming sick. And that's really the key intervention that we have available to us.

Chris - The current UK government guidelines are that we can try to use the vaccine in people who have been exposed. It's almost like a prophylactic measure. It gives the immune system a bit of a head start and it seems to cut down the number of clinical cases we get. Is that likely to become part and parcel of what we do in places like the Democratic Republic of the Congo where we've got big numbers of cases, we can go in and try to rein in the outbreak by protecting people who've been exposed.

Michael - So there are two broad approaches you can take. There's what we call pre-exposure vaccination. So that's taking people who are at risk and vaccinating them before they're exposed. And then there's post-exposure vaccination. The scenario you are describing, I come into contact with someone, you try and vaccinate me. Most of the data we have so far suggests that pre-exposure vaccination is much more effective. And that's probably because you're giving the body's immune system time to really respond to that vaccine and protect you. Whereas if you vaccinate someone after they've already been exposed, in fact they may already be infected and you may not fully have a chance for the vaccine to work. So the ideal scenario is that we have enough vaccines available that we can roll it out at scale to all the people who are living in areas where there are many, many cases of mpox at the moment before they are exposed. Of course, some of those individuals will be exposed and so they will effectively get post-exposure vaccination, but we really are likely to need widespread vaccination of many, many people to curtail the outbreak.