Since May, there have been a lot of stories in the news about monkeypox. Depending on which stories you read, you may have heard that it's not very contagious, or that it's very contagious. You may have heard that it's not very dangerous, or that it's very dangerous. It's confusing. But we can help.
To help get a handle on what we know about monkeypox, we spoke with Julie Swann and Matt Koci. Swann is a systems engineer with expertise in public health whose work focuses on making health care more efficient, effective and equitable. Swann is the department head and A. Doug Allison Distinguished Professor of the Fitts Department of Industrial and Systems Engineering at NC State. Koci is a virologist and immunologist whose work focuses on host-microbe interactions; he is a professor in NC State's Prestage Department of Poultry Science.
The Abstract: So, first question: what is monkeypox?
Matt Koci: Monkeypox is a virus. It belongs to a family of viruses known as the pox family which contains the smallpox virus, camelpox and cowpox viruses, just to name a few of its close relatives.
However, because names in science don't always make sense, chickenpox isn't a pox virus. Keeping with that theme, while monkeypox is a pox virus, it should probably be called rodentpox, since they are the more common carrier of the virus.
This isn't like SARS-CoV-2. Monkeypox isn't a new virus. We've actually known about this virus since 1970. There have been several outbreaks of monkeypox over the past 50 years. Most have occurred in western Africa, but we've seen several outbreaks around the world. Most of these start off with someone who recently returned from a trip to Africa. One major exception to this pattern was a 2003 outbreak here in the U.S. that ended up affecting 71 people. The culprit in this case was an infected prairie dog that was purchased as a pet. It was later discovered that the prairie dog got it from Gambian pouched rats imported by an exotic-animals dealer.
But while this isn't a new disease, something is different this time. This current outbreak has spread to over 76 countries, infected over 19,000 people, and lasted longer than any other previous outbreak. Right now, we don't know why that is, but early evidence suggests the variant of monkeypox associated with this current outbreak has evolved to spread from person-to-person more efficiently than we've ever seen monkeypox do before.
Julie Swann: I agree with all of that. The summary is that monkeypox is a virus that has jumped from animal hosts to humans, and it is now spreading between or among humans independently. The current outbreak is human-driven and not related to monkeys or other animals. In the coming years, we will likely continue to hear about diseases that gain the ability to make human-human transmission and spread in new ways or to new populations. Monkeypox is not as easily spread as the virus that causes COVID-19, although the number of new cases and new geographical locations is staggering.
TA: How hazardous is monkeypox to human health? Is it fatal? Does it leave scars?
Koci: There are a lot of diseases that are worse than monkeypox. From a public health perspective COVID-19 is still a much bigger issue, but that doesn't mean we can ignore monkeypox. While monkeypox disease typically clears on its own in about 2 to 4 weeks, it's going to put painful blisters in places the sun don't shine for days to weeks. More severe illnesses that require hospitalization can happen, especially in kids and the immunocompromised. Looking at previous outbreaks, case fatality rates have been as high as 3-6%, but so far during this outbreak while there have been a few deaths globally, the case fatality rate is well under 0.1%, and none have been reported in the U.S.
If you've been infected, symptoms typically start between five and 13 days later, but could be as long as three weeks later. Recent data from the current outbreak in the U.S. suggest the three most common first symptoms people report experiencing is fever (41% reported fever as the first symptom), rash (41%), or chills (16%). Regardless of what the initial symptoms were, patients reported several symptoms, some more common than others: rash (100% reported experiencing a rash at some point during the their illness), fever (63%), chills (59%), lymphadenopathy (swollen lymph nodes, 59%), malaise (general discomfort, 57%), myalgia (muscle aches and pains, 55%), headache (51%), rectal pain (22%), pus or blood in stools (21%), abdominal pain (12%), rectal bleeding (10%), tenesmus (feeling like you have to go #2, but there's no #2 to go, 10%), vomiting or nausea (9%).
The one symptom that everyone seems to experience is the tell-tale rash and blisters. These have been reported all over the body: genitals (46% reported experiencing a rash and/or blisters here), arms (40%), face (38%), legs (37%), perianal (between the buttocks and around the rectum, 31%), lips and mouth (25%), palms of hands (22%), trunk (22%), neck (18%), head (14%), soles of feet (11%). This normally clears up after 2-4 weeks; however, more severe cases requiring hospitalization can occur, especially in young children and the immune compromised. The rash and blisters can be quite painful, and can lead to scarring after they clear up.
Swann: Previously, monkeypox has had two genetic groups (or "clades"). The group in the Congo Basin in central Africa has had higher fatality rates (e.g., sometimes 10%), while the group in west Africa has had lower rates (e.g., 1%). So far, the variants that are circulating in the U.S. have had even lower fatality rates although there have been deaths. A number of patients are reporting significant pain, and the symptoms can last for weeks.
One of the concerns is not only the individual cases and outcomes that we are seeing, but also the possibility that the disease will become endemic in broad, new areas of the world. This possibility becomes more and more likely the slower the response to contain it.
TA: How contagious is monkeypox?
Koci: The good news here, at least historically, is that monkeypox doesn't spread as well as smallpox did, and it certainly spreads a lot slower than COVID-19. However, I say historically because while we've had outbreaks of monkeypox in the past, those outbreaks have burned out after a few days, with very limited human-to-human spread.
