With the recent declaration by the World Health Organization (WHO) that the clade I mpox outbreak originating in the Democratic Republic of the Congo has become a Public Health Emergency of International Concern, it’s easy to get a spooky feeling of déjà-vu. Just over four years ago, the same agency was describing COVID-19 as the “most severe” health emergency ever.
But it’s important to remember that we’re talking about two very different diseases – mpox is not another COVID-19. There are some very important reasons why the WHO has called for another emergency response, but we are not seeing a repeat of the early months of 2020. And here’s why.
Mpox and SARS-CoV-2 are different types of viruses
This might sound obvious, but it’s a good place to start. Mpox and SARS-CoV-2, the causative agent behind COVID-19, belong to two very different families of viruses.
SARS-CoV-2 is a coronavirus. It’s a big family of viruses that mostly only cause mild cold-like illnesses in humans, but SARS-CoV-2 joins two others that can cause much more serious disease: SARS-CoV, the original SARS virus, and MERS-CoV, which causes Middle East respiratory syndrome (MERS).
SARS-CoV-2 is an enveloped virus with a single-stranded RNA genome. It only encodes a small number of proteins, and just four that are necessary to maintain the structure of the virus. One of these is the spike protein, which has become infamous in the last few years as the means by which the virus gains access to our cells. The spike protein is also the key target of the mRNA vaccines that altered the course of the COVID pandemic.
Mpox, on the other hand, is a poxvirus. Their internal structure is quite different from that of coronaviruses: their genomes are double stranded DNA, not RNA, and they have much greater complexity. They do also have an outer envelope, but it has a large number of proteins that can allow them to enter multiple cell types.
COVID-19 took the world by surprise, but humankind has a lot more experience dealing with poxviruses. Smallpox remains the only human disease to have been completely eradicated, thanks to vaccines, but it used to kill millions of people every year. Thankfully, no strain of mpox we’ve yet seen has anything like that kind of case fatality rate.
Mpox and SARS-CoV-2 are spread differently
As you might expect, these two very different types of viruses are also spread in different ways.
We’ve only been dealing with SARS-CoV-2 for a relatively short amount of time, and our understanding of how it spreads has been developing as we’ve been trying to figure out how best to respond to the threat.
Early in the pandemic, many suggested that contaminated surfaces were a key point of transmission, leading to a large emphasis on handwashing, cleaning, and sanitizing (remember wiping down all your groceries?). Edicts like the “2-meter rule” for social distancing aimed at limiting transmission via close contact with infected people through respiratory droplets.
Critics at the time believed that this shifted focus away from the role of airborne transmission, a debate that was complicated by mixed messaging around what “airborne transmission” actually meant. The WHO staunchly maintained that COVID was not airborne for much of 2020.
Now, almost five years in, we understand a lot more about how COVID spreads and we know that it can linger in the air, and be transmitted over greater distances than many initially thought. Ventilation and air filtration are now considered important elements of a COVID-19 mitigation strategy.
For mpox, the situation is rather simpler. The disease spreads through close contact with an infected person, which includes sexual contact, and occasionally via contaminated objects and surfaces. Someone can be considered infectious until all of their mpox sores have completely healed, but the virus can persist on surfaces for some time if they’re not disinfected.
One bit of good news is that as enveloped viruses both mpox and SARS-CoV-2 should be susceptible to most hand sanitizers, if soap and water are not available.
Mpox and SARS-CoV-2 cause very different diseases
You’re probably sensing a theme here. Mpox and COVID-19 are very different diseases with different risk profiles, and it’s important that health authorities respond to each one appropriately.
Scientists are learning more every day about what the SARS-CoV-2 virus does once it gets inside the body. What we do know is that multiple organ systems can be affected, which helps explain the wide variety of symptoms people experience. Not everyone exposed to the virus gets any symptoms at all, of course, and human challenge studies have helped shed some light on how certain people’s immune systems seem better at fending it off. There’s also the issue of long COVID, where some people develop lingering health issues even after a comparatively mild initial infection.
There are so many questions yet to be answered, and we’re going to be seeing more new research findings for years to come.
Mpox has been around longer, and thus we have a better understanding of how it operates. The virus can enter the body via the mouth, nose, or through breaks in the skin. This point of entry is known as the inoculation site, and the virus begins to replicate here before spreading to the lymph nodes. It gains access to other organs via the lymphatic system, during an incubation period that can last up to 21 days in some cases.
The initial symptoms generally include a fever, headache, and muscle pain – quite non-specific, and hard to pin down as mpox. This lasts a couple of days before the characteristic rash starts to appear, as lesions that can affect any area of the skin and also the inside of the mouth and throat. The blisters can be itchy or painful, and may persist for up to four weeks.
For both diseases, treatment for more severe cases can include antiviral medications and hospitalization, but for most people, the focus is on relieving the symptoms while the disease runs its course.
There’s no question that the arrival of vaccines changed everything with COVID. They don’t completely prevent someone from becoming infected with the virus – although they do offer a reasonable degree of protection on that score – but they’ve made a huge difference when it comes to severe disease and death.
There are currently two approved vaccines for mpox as well, and authorities are trying to get more doses into the worst-affected regions. Public health messaging that explains who is at risk and how eligible people can access a vaccine is also key.
The bottom line
When you get right down to it, there are few similarities between mpox and COVID-19. We’re not walking into another lockdown situation.
The WHO’s Europe regional director Dr Hans Kluge recently spoke at a press conference, confirming that this time around, we have many of the tools we need to stop the spread of mpox – not least because we’ve just experienced an outbreak affecting dozens of countries, albeit with a less lethal variant of the virus, beginning in 2022.
“Two years ago, we controlled mpox in Europe thanks to the direct engagement with the most affected communities of men who have sex with men,” Dr Kluge said, as reported by the BBC. “We can, and must, tackle mpox together – across regions and continents.”
But there was also a warning mixed in. “Will we choose to put the systems in place to control and eliminate mpox globally or will we enter another cycle of panic, then neglect?” Dr Kluge asked.
Mpox is not COVID – but that doesn’t mean we can or should ignore the lessons that COVID has taught us as we mobilize against the latest threat to global public health.
Source Link: Why Mpox And COVID Are Very Different Viral Infections