Will Monkeypox Be The Next Deadly Pandemic? It’s Unlikely
Infectious disease expert Mark Kortepeter explains the differences between Covid and monkeypox and how its spread primarily through direct contact rather than respiratory droplets means it’s less likely to cause a pandemic as significant as Covid.
More than two years into the Covid-19 pandemic, our surveillance networks are on heightened alert for what might be the next big thing. We didn’t predict Covid, and we have never correctly predicted the next infectious disease of concern. If someone had asked me what I thought might be next, I certainly would not have predicted monkeypox, even though I teach regularly about the threat of its close cousin, smallpox.
In the past two weeks, we were alerted to an outbreak of monkeypox that began in Europe and thus far appears linked primarily to men who have sex with men. The numbers of confirmed cases worldwide are over 200 and climbing. There have been few cases confirmed in the United States so far, but that could change. The public is naturally concerned about yet another disease suddenly appearing that they may have never heard about before. One key question people might ask is “Will this be as bad as Covid?”
My short answer is – “not likely,” but that doesn’t mean we shouldn’t be concerned.
What causes Covid and monkeypox?
These are two completely different viruses, and they behave differently in human populations. Covid is caused by the SARS-CoV-2 virus. It is a coronavirus, so named, because the virus appears round on electron microscopy surrounded by a sun-like corona. Monkeypox is caused by the monkeypox virus, which is in a different family of viruses, the poxviruses.
A brief history of Covid and monkeypox
SARS-CoV-2 was first identified in late 2019 as a brand new virus. Since then, we are all too familiar with how it has spread all across the world and affected every continent. Monkeypox first surfaced in humans in the 1970s in central Africa after the eradication of its close viral, but more deadly “cousin,” (from the same genus) Variola, which causes smallpox. [KJ4] [MK5] There are occasional infections in U.S. individuals after they have travelled to parts of Africa where monkeypox occurs. For example, there were two cases last year.
In 2003, there was an outbreak of monkeypox in the Midwest. The source of the outbreak was African rodents that were imported to the U.S. and comingled with prairie dogs, which in turn infected humans who traded them as pets. This outbreak demonstrated the ability of monkeypox to spread beyond its traditional geographic areas of risk, perhaps foreshadowing the potential for the current outbreak. What is unusual about the cases that have been identified recently, and which has public health authorities on heightened alert, is that the infected patients have not travelled to Africa. This means they have either had direct contact with an infected animal or infected person. Public health authorities are in the process of conducting an outbreak investigation to determine how the disease is spreading.
How the symptoms of Covid and monkeypox compare
Covid can start out with body aches, a sore throat and fever, but it primarily affects the respiratory tract, leading to cough and shortness of breath. Monkeypox starts with 2-4 days of fever and fatigue, followed by development of a characteristic rash with pus-filled lesions. The rash can be localized to specific areas or occur on multiple parts of the body, including the face and hands. Lesions around the genitals have been reported in this outbreak. Other findings include swelling of the lymph nodes in the neck, and sore throat. In the earliest couple days, before other characteristic features appear, it might be hard to distinguish the two based on symptoms alone.
How the spread of Covid and monkeypox compares
As a respiratory virus, Covid spreads primarily through the air, when you inhale the respiratory secretions of someone while they are talking, singing, coughing, or sneezing. The majority of monkeypox infections historically have occurred due to direct contact with animals. Various animals in Africa are known to harbor the infection, including Gambian rats, squirrels, and dormice, but human-to-human close contact is also recognized as a method of spread. This means direct contact with fluid from skin lesions or other body fluids, and respiratory droplets, as well as clothing or bedding contaminated with body fluids. One concern with the current outbreak is whether spread is occurring through sexual contact. If so, it may not be so simple to contain.
The vaccines available against Covid and monkeypox
Three vaccines are available in the U.S. to prevent Covid, which are either licensed or available under emergency use authorization. These vaccines contain genomic material that is injected into your muscle. Your body then makes proteins and mounts an antibody response to them.
There are two vaccines licensed against monkeypox. One that is injected is licensed by the FDA for both smallpox and monkeypox. The other is licensed against smallpox, but has been used to prevent monkeypox during the 2003 outbreak. The latter is given by taking a small amount of virus in liquid and poking it into the skin with a specialized bifurcated needle. A local pus pocket soon develops that eventually leads to a dime-sized to quarter-sized scar on the upper arm. These scars, often seen on individuals born before the 1970s, provide a permanent demonstration of prior vaccination.
The treatments available against Covid and monkeypox
Several treatments against Covid have been developed and have been used during the ongoing pandemic, including antivirals such as Paxlovid and Remdesivir. There are a few antiviral treatments that have been developed to threat a smallpox outbreak, but whether they would be effective against monkeypox has not been extensively studied.
Will monkeypox cause a pandemic?
We have already seen cases occurring on three continents (not including where it generally resides in Africa), so that is a possibility, unless we can determine what specific types of activities are facilitating the spread and interrupt the transmission. However, monkeypox requires much closer contact to spread than Covid, so based on what we know about it, it is unlikely to cause the kind of explosive spread that we saw with Covid.
There are some key distinctions compared with Covid: it is nearly impossible to distinguish Covid from other respiratory viruses, so it is much harder to avoid. In addition, asymptomatic individuals can spread the virus unknowingly. Monkeypox is not known to cause asymptomatic disease, but individuals previously vaccinated with the smallpox vaccine (fewer and fewer with each passing year), may have reduced symptoms. Having said that, the pus-filed rash is easy to identify if it is on a visible body part, although it could be confused with chickenpox and numerous other rashes. Hence the need for confirmatory viral testing.
The genomic material in the two viruses is different: coronaviruses have RNA and poxviruses have DNA. This is a key distinction, because RNA viruses tend to mutate more easily when they reproduce than DNA viruses, which have more stable genomes. This feature has allowed Covid to continue to spread in multiple waves across the world with each new variant.
Is monkeypox deadly?
The Congo Basin variety of monkeypox can have death rates up to 10% of those infected. But the good news is that is not what we are dealing with. The current outbreak is caused by the West African variety, which is far less deadly (less than 1% fatality rate). No people with confirmed cases have died thus far.
We are in the early stages of understanding this outbreak. No doubt the situation will evolve and so will our understanding of how it is spreading and how to contain it.