Are we ready for the next potential pandemic? It seems like we are just get over COVID and already we have to worry about the next one. We first covered the monkey pox (now mpox) in 2022. Since then it has continued to be a concern. Where do our efforts to contain this infection stand?
To recap, the disease mpox is the result of a viral infection with the monkeypox virus. This is a virus closely related to smallpox – a member of the Orthopoxvirus genus in the family Poxviridae – the same genus as smallpox. It also causes a similar infection with fever, a pox-like rash, and inflamed lymph nodes. It is spread mainly through direct contact and bodily fluids, although can be spread from contaminated objects, and can be airborne (although this is not a major route of infection).
Monkeypox is a zoonotic virus, meaning that it has animal reservoirs and can spread from animals to humans, mostly rodents, monkeys, and small mammals. There are two clades of the virus. Clade I is endemic in central Africa, causes a more severe illness with fatality rates up to 10%, but recently has been in the 2-3% range. Clade II is endemic in West Africa and is less severe, with a <1% fatality rate.
Clade II (IIb to be precise) is what caused the global outbreak in 2022 that we previously wrote about. This caused 95,000 cases in 115 non-endemic countries, including the US. There are still new cases of mpox in the US in 2024, although trailing off with no new cases reported in the last month.
Now we are facing a potential outbreak of Clade I mpox. The WHO on August 14th declared a Public Health Emergency of International Concern regarding the growing number of cases in endemic and non-endemic countries in Africa. There have also been cases in Sweden and Thailand in people with recent travel to Africa. The concern is that this can cause a global outbreak similar to the 2022 Clade II outbreak, but with the more severe strain with higher mortality.
One big advantage we did not have in the early days of COVID is that we already have an effective vaccine against mpox, the JYNNEOS vaccine. This is indicated for the prevention of both smallpox and mpox. The CDC has already distributed over 1 million doses in the US to people who are considered at risk. There is not enough vaccine for the general population, and a full population rollout is likely not necessary.
The concern right now, however, is that there is not enough vaccine to fully control the disease spread in Africa. This is part of what has the WHO concerned, cases of clade I are increasing, spreading to non-endemic countries, and there isn’t enough vaccine to stop it. The US and other countries are donating doses of vaccine, personnel, and funding for efforts to treat the disease in Africa, but so far it is not enough. There simply is not enough vaccine manufactured at this time. There are plans to ramp up production, but that takes time.
The risk of a clade I mpox outbreak brings home a couple of realities. First, we now have to accept that we live in a world with a baseline high risk of zoonotic infections spreading to the human population. The primary reason for this is the increasing human population and corresponding land use. This overlap in human and animal populations will increase significantly over the next 50 years.
It is also important that we recognize that disease outbreaks in any part of the world can potentially affect everyone. A virus that spread in a meat market in Wuhan China became a massive worldwide pandemic killing millions. Now we have a virus endemic only in central and west Africa but with the potential to cause worldwide outbreaks. This means that it is in our and everyone’s interest to have a rapid and definitive response to infectious disease outbreaks wherever they may occur. Not only is this the right thing to do from a humanitarian perspective, but by treating outbreaks abroad we prevent outbreaks domestically.
We are being caught a little flat-footed again with the mpox outbreak, although our response is better than in the early days of COVID. We also have an effective vaccine, and so it is worth investing resources in getting this vaccine to everyone who needs it. Our goal should be not just containment, but elimination of the virus in Africa to prevent further outbreaks.
It may already be too late. Monkeypox will be difficult to eliminate and may be impossible to eradicate because it has animal reservoirs. This is something else we need to prevent – allowing the virus to establish new endemic animal reservoirs.
We may simply need to invest far more resources into surveillance and response to potential zoonotic diseases. There are many potential agents out there. There continues, for example, to be outbreaks of ebola, which can have up to a 50% fatality rate. The largest outbreak so far was the 2014-2016 outbreaks, but there have continued to be smaller one through 2023.
Because the world is now so interconnected, all it would take is for an outbreak to hit even a moderate-sized city, or any city with significant international travel, for an outbreak to become an epidemic or even pandemic. We are all in this boat together, and so we need to have a rapid and robust response to infectious disease outbreaks wherever they occur in the world. The mpox is just the latest reminder of this reality.
