As summer winds down, many of us have been hearing or reading about how many states across the country are experiencing another surge of COVID-19, the biggest wave we’ve seen in at least two years.
Recently, another major infectious disease—known as mpox—has also been generating headlines. In mid-August, the World Health Organization (WHO) and Africa Centers for Disease Control (CDC) declared the virus a public health emergency, “of international concern,” and “of continental security,” respectively.
Last week, Daniel Lucey, MD, MPH, (D'77, MED'81) a clinical professor of medicine at Geisel and internationally known infectious disease specialist who has fought a number of epidemics over his 40-plus year career, provided an update on mpox to the Dartmouth community. In the following Q&A, he shares details about the epidemic and efforts to fight it.
Q: What is mpox?
Lucey: mpox is a DNA orthopoxvirus related to smallpox (which was declared eradicated in 1980). It causes skin lesions like smallpox but it is considered to be much less deadly and less contagious than small pox. It spreads between people mainly through close contact and can also be transmitted from infected animals to people who have contact with them. People who are immunocompromised are at higher risk for severe mpox.
The first patient identified with mpox was in 1970 in the Democratic Republic of the Congo (DRC), formerly Zaire, and the virus was first discovered in monkeys in Denmark and the U.S. That’s where the misnomer of “monkeypox” came from—it turns out that monkeys are actually not the natural reservoir of the virus.
Traditionally, mpox was divided into two clades or strains, Clade 1 (Central Africa) and Clade II (West Africa). In general, it’s considered that Clade 1 has a higher fatality rate than Clade II, perhaps as high as 10 percent compared to around 1 percent. The primary focus of the recent international declarations is a new genetic variant known as Clade 1b, in addition to the ongoing Clade 1a epidemic, in four nations bordering the DRC.
Q: What are the animal reservoirs of mpox, if not monkeys?
Lucey: In 2003, an mpox outbreak in the U.S. involving 71 patients in six Midwestern states, was linked to imported animals from Ghana and West Africa to a pet store in Texas.
Laboratory testing by the CDC found mpox in three small animal species—giant pouched rats, dormice, and rope squirrels. After they were imported into the U.S., some of the infected animals were housed near prairie dogs at the facilities of an animal vendor. The prairie dogs were sold as pets before they developed signs of infection. So, I would argue that at least the three species involved can be infected naturally or are a source of mpox virus.
Q: Why did the Africa CDC make the declaration of mpox being a “public health emergency of continental security” now?
Lucey: According to their announcement, it was driven by the worsening mpox situation on the continent since 2022, with more than 40,000 cases of mpox and over 1,500 deaths reported due to mpox in 15 African Union member states. Generally, what’s been emphasized so far about Clade 1b is it’s more serious than the previous outbreaks with Clade 1a or Clade II.
In addition, they state that in 2024 alone, 17,541 cases and 517 deaths have been reported in 13 African Union member states, of which the DRC has 96 percent of cases and 97 percent of deaths.
While this was the first-ever declaration by Africa CDC of a “public health emergency of continental security (PHECS),” it was the second time the WHO has declared mpox a “public health emergency of international concern (PHEIC),” the previous time was in July 2022 for Clade II mpox and spread to many nations including the U.S. So far, no persons have been reported in the U.S. with the new Clade 1b mpox infection. This is the WHO’s eighth PHEIC over the past 15 years, with the first being the 2009 H1N1 pandemic.
Q: Are there effective vaccines or therapeutics for mpox?
Lucey: It turns out that the smallpox vaccine protects against mpox. It uses the “vaccinia” virus, not the smallpox or mpox virus, so it can never give you smallpox or mpox. We’ve had an FDA-licensed vaccine for mpox for several years. And while it has been available to countries in Europe and the U.S. (including during the Clade II many nation “pan-epidemic” that led to a WHO PHEIC in 2022), it has not been available in Africa where it is most needed.
A recent study (co-sponsored by the NIH and DRC) of the main antiviral drug for mpox called Tecovirimat, didn’t show any improvement in patients with Clade 1 mpox.
Through a partnership with Bavarian Nordic, and support from the European Union, U.S. and Japan (donating a different vaccine used in Japan in the 1970s called “LC16”), Africa CDC has pledged to deliver 10 million mpox vaccine doses by 2025, marking a significant commitment to strengthening health security across the continent. This partnership is set to play a crucial role in ensuring that up to two million doses are available this year.
Q: What are some key takeaways that you would like people to remember regarding the rapidly evolving situation with mpox?
Lucey: The international response to the 2022 WHO mpox declaration for Clade II was terribly inadequate, with no vaccines made available to African nations where the virus is endemic and epidemic. And now, in 2024, both Clade II and the new Clade 1b are still causing epidemics in multiple nations. The global community must respond more effectively and comprehensively.
The African CDC, under the authority of the African Union, is taking a new and much stronger leadership role in declaring its first PHECS, and emphasizing the need for equitable vaccine access across African nations. In addition, the transmission routes, especially involving children (whether Clade 1a or 1b), and severity of this new Clade 1b must be understood as soon as possible.
A final point is that there are always outbreaks going on, and there are many of them happening right now around the world, this is just the one we’re hearing most about. As I often say to students in every class I teach—"What’s next is already here, we just haven’t recognized it yet.”
