Why Monkeypox and Why Now? The Mystery Behind the Current Outbreak

Salvador Macip, MD, PhD


June 03, 2022

Monkeypox. It's all about this now. Never mind that we haven't yet finished with COVID-19, very much alive and kicking despite being ignored in many countries. The news of an unprecedented outbreak of this rare disease, usually confined to central and Western Africa, has brought back echoes of early 2020, with fears of a new pandemic spreading like wildfire. But this is a whole different game.

To start, this disease is not caused by an unknown agent, like SARS-CoV-2 was at the time, but by a well-studied distant relative of the smallpox virus that we've known since 1958. The bad news is that, if left untreated, monkeypox has a mortality rate of 3%-10%.

But there has been plenty of time to understand how it spreads and even work out which drugs it is sensitive to. We even know that the smallpox vaccine (which most adults over 50 received when they were kids) offers good protection, up to 90%. We are much better prepared this time.

There are more positive facts. Contagion happens only in very close-contact situations and, contrary to what we've seen with COVID-19, patients can infect only once they have symptoms. Avoiding intimacy with those with a suspicious rash or fever cuts your risk of catching it tremendously. That's why monkeypox outbreaks usually are small and controllable: It's a poorly transmitted disease. It can be caught from infected animals too, usually rodents (monkeys got the bad rap for historical reasons but are not the most common reservoirs), although this is rare in urban environments.

But the current outbreak is different. For the first time in history, it spans over 30 countries and includes 658 cases, as of the time of writing. So far, there are no reported deaths — at least there's a silver lining. There had been outbreaks before (including one with over 70 cases in the US in 2003 due to imported Gambian pouched rats) but none of this magnitude, so spread out and so difficult to trace. It seems that patient zero may have been a Brit who traveled to Nigeria and perhaps got the virus from a wild animal, but the chain of transmission quickly gets blurred after this.

The first explanation that jumps to mind would be that the monkeypox virus acquired a new mutation that made it more infectious, like we've seen happening to SARS-CoV-2 many times in these past 2 years. But this doesn't seem to be the case because the sequencing of the viral genome so far revealed no major changes; it seems to be identical to the viruses that roam Western Africa (which, incidentally, are the less lethal of the family, with a mortality rate of only 1%). There could be a new way of spreading it: sexual contact. This has not been reported before. But with the fact that sexual relations usually need people to be in close proximity, it may just be a coincidence.

A more worrying hypothesis that is being considered is that COVID-19 has "primed" us for other diseases. Two years of severely reduced exposure to pathogens (due to lockdowns, social distancing, masks, and hand washing) could have weakened our immunity, making us more prone to catching microbes that previously were kept in check.

Alternatively, it could just be that if you had COVID-19, other subsequent infections behave differently and give unexpected results. The recent cases of severe hepatitis in children, also a rare event suddenly magnified, could be another example of this. We have no way of knowing yet whether COVID-19 had anything to do with the monkeypox outbreak, and perhaps we will never know, but this possibility is as interesting as it is scary.

What now? The monkeypox outbreak is likely to die out in a relatively short time, due to the characteristics of transmission discussed earlier. It may do so without leaving mortal victims, if we keep the same rate. Now that the general public is aware (and often afraid), it will be easier to avoid risky situations. Vaccines and drugs should further reduce serious events.

But the main question is, are we going to see more rare infectious diseases jumping into the spotlight in the next months as a remote side effect of the pandemic? Is one of them going to be truly problematic on a worldwide scale? Let's hope the answer is no.

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About Dr Salvador Macip
Salvador Macip, MD, PhD is a doctor, researcher and writer. He obtained his MD/PhD at the University of Barcelona (Spain) in 1998, then moved to do oncological research at the Mount Sinai Hospital (New York). Since 2008, he has led the Mechanisms of Ageing and Cancer Lab at the University of Leicester (UK). Macip has published over 30 books, including Where Science and Ethics Meet (2016) and Modern Epidemics (2021). Connect with him on Twitter: @DrMacip


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