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Linchuan Zhang asked and paid me to write this up.


Basically no. The disease remains highly confined to the gay community. The chances of it becoming a seriously threatening pandemic like Covid-19 are low.

If you are a sexually active gay man , it is likely wise to limit your number of sexual partners as you are at a large risk.

The largest and hardest to quantify threat is a mutation. Additional concern here due to APOBEC3.

Has Monkeypox growth gone linear?

We are just shy of 3 months since tracking of Monkeypox began. As of Aug 5th, there are ~800 cases per day worldwide. At this point in Covid, there were ~82000 per day worldwide. In the US, there are ~300 cases per day. For covid, there was ~30000 per day. Covid was ~100x further along. Now, this doesn’t prove that Monkeypox isn’t undergoing exponential growth but it does suggest that it isn’t as fast. Furthermore, some look into the charts at Our World in Data seems to show that growth isn’t accelerating fast worldwide.

According to this article on the 29th, monkeypox was growing “exponentially” at 5000 cumulative cases in the US, and predicted that that number would grow every week to 10000 (by August 5th). The current number is ~7000. Worldwide, the 7-day average has remained between 800-900 for around 10 days. Due to the number of unreported cases, it of course could be growing exponentially but the data doesn’t seem to suggest this.

It is still too early to call but it’s likely that this strain is no longer growing exponentially.

Real vs Confirmed Cases

A big lesson from Covid was not to treat confirmed cases as the only cases. Due to the fact that monkeypox looks different on everyone and the typical case doesn’t look like pictures on the internet (monkeypox usually presents simply as some discoloration in the area of infection, often near a genital area), my 90% confidence interval is that there is an additional 100-800% of cases currently unreported. This number is particularly high due to the usual symptoms being unlike pictures on the internet and due to the fact that in Africa, where I suspect there may be many unreported cases due to infrastructure and a higher stigma surrounding homosexuality. 

Gay Community

Depending on where you look 95%+ of cases seem to be transmitted sexually between gay/bisexual men. This study reports 98% of cases being gay/bisexual men. Nearly all cases are contracted through sexual activity among men having sex with men. I would guess that due to some stigma surrounding gay sex in certain countries, it’s possible that all but a few cases have been spread through sexual activity between men. As an aside, if you are someone who has sex with other men, it would probably be a good personal decision to limit your number of partners. While Monkeypox spread is rather limited to the gay community thus far, it is certainly not saturated in the gay community, particularly among those who are sexually active. As a quick BOTEC, New York has the most cases in the US. There are about 20M people in New York, 50% are men and about 5% are gay/bi which is 500,000 men. Maybe 40% are sexually active so we are looking at 200,000 gay men in New York state. About 2000 men in New York have a confirmed case of Monkeypox.


Probability of Escaping the MSM Community

If the disease spreads far, at some point the disease would escape the gay community since it is technically spread through skin-to-skin contact, not an STI. Many other skin-to-skin activities exist (martial arts, etc.) and it is likely possible to spread through surfaces (towels, sheets, etc.). At 10,000 cases in the US, it is likely to stay within the gay community. At 100,000 cases, I expect an over 50% chance that it escapes the gay community.

Mutation Rate

I’ll preface this section by stating I have little background in genetics/biology at the necessary level. 

It seems that the current strain is linked to a high number of ~50 mutations from cases isolated in 2018/2019. This is a large number of mutations, much larger than expected for Orthopoxyviruses (where 1-2 mutations per year are expected). This is about an order of magnitude more than one would expect for this virus. For example, there are 46 single nucleotide polymorphisms (SNPs) that separate the current strain from a 2018 strain. Among these 46 SNPs, what is concerning is that there is a strong mutational bias with 26 being GA>AA and 15 being TC>TT. This and some further evidence suggests that apolipoprotein B mRNA-editing catalytic polypeptide-like 3 (APOBEC3) enzymes have a role in MPXV (monkeypox virus) evolution. Further evidence of APOBEC3 is seen by the fact that MPXV is A: T rich.

This is the most worrying aspect of Monkeypox, that APOBEC3 enzymes are present and causing non-random mutations. To get a better idea of how scary this is, I’d want a better idea of how common these mutation-accelerating enzymes are. Preliminary research suggests they are uncommon but not rare. Current MPXV doesn’t seem that serious and spread is slow, and mortality is slow but there could be a significant mutation risk. See this Nature article to read more about where I got a lot of this information.


Monkeypox is typically not very virulent. Mainly flu-like symptoms and a rash. I can’t find any QALY estimate but using the one for symptomatic HIV of ~0.82 seems reasonable. There have only been 9 deaths among those with confirmed cases out of ~30000 infections which is a death rate of 0.03%. For comparison, Covid has a death rate of ~1% of confirmed cases

Cost-effective Intervention?

Very rough calculation.

Assuming that mutation risk gives a 5% chance that monkeypox could spread as far as covid, to ~1B cases, given the death rate of 0.03%, monkeypox could kill around 300,000 people. Given a 5% chance of it getting this far on its own, we are looking at a worst-case scenario of averting the deaths of around 15,000 people. For an intervention to be cost-effective, it would need to cost on the order of $50M to eliminate the chance of spreading as far as Covid. At this rate, simple solutions like paying gay men to abstain from sex becomes impractical.


Monkeypox is concerning and should be monitored but EAs shouldn’t yet spend significant time worrying about it or diverting their attention from typical cause areas.






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I think your post comes across as a little tone-deaf in a way that can be counter-productive.  

"Is it worth worrying about?" "Basically no. The disease remains highly confined to the gay community."

Comes across as a disregard to the LGBTQ community. Mostly because of the historical context in which we live.

This sentence echoes many things that were said during the AIDS pandemic, which prior to COVID was the closest we got to GCBR in the past 100 years and in many metrics is closer to a GBCR than COVID.  Historically there was a very intentional disregard for the AIDS pandemic because  its devastating effects were mostly confined within the LGBTQ community. [link] The Reagan administration famously told the CDC "act pretty and do as little as possible." This policy lead to a lot of preventable deaths and suffering.

"simple solutions like paying gay men to abstain from sex becomes impractical" 

Is it a simple solution? I never heard of any sort of successful policy where people were paid to stop having sex. I think abstinance-only sex-ed shows that it's very hard to convince anyone to stop having sex even when people are taught to internalize to avoid it categorically and the stakes are high (other STIs, teen pregnancy...). I think you should either remove this sentence or give some thought & add something about encouraging using protection and STI testing that includes monkeypox. More practically, I do think these policies have a better track record too.

This information is important, and you spent significant time reading on it and writing it up. It's important to communicate it without hurting a whole group of people, and I think that with a bit more thinking it can be done.

I actually agree here that the solution proposed is not going to work (At the very least, STI testing and condoms work far better than abstinence-only sex-ed.) I however want to point out that HIV/AIDS was probably not going to be a GCBR, let alone Monkeypox as it indeed happened historically for that pandemic.

The biggest reason is that viruses/bacteria/protozoa/fungi that are severe, spread widely and can't be stopped by the immune system is very hard (naturally speaking.) Thus there's a problem for GCBRs to actually happen, and the only one that vaguely meets the criteria is the Black Death in Europe.

"Comes across as a disregard to the LGBTQ community. Mostly because of the historical context in which we live."

I tried to strike a bit of a balance. Current reporting on monkeypox, particularly from government agencies/public health officials have been pretty terrible, trying to downplay that MPXV is predominantly spreading through sexual activity between men. It has improved a bit but the CDC website, right now, says absolutely nothing about it spreading through MSM. This is so egregiously misleading it amounts to misinformation.

Is it a simple solution?

I made this post because Linch asked me to research a bit and then write up what I found. We had a brief call about what he was thinking and wanted covered and among them was if it was worth it to try and stop the spread by paying people to refrain temporarily. This isn't a crazy idea. If we were very early on, I might even recommend this course of action. It's a simple solution insofar as it is pretty simple to describe and if funded, could be put together quickly. Identify those most likely to spread the disease and pay them $25/day to not have sex (or just have sex with a single partner). I suggest this is no longer possible. Nonetheless, this shouldn't be thought of as an STI. Using protection (condoms, etc.) would do approximately nothing in my estimation and monkeypox is not an STI, it is simply spreading primarily at this point through gay sex and wouldn't come up on a test for STIs.

(1) I never purported that communicating that monkeypox is transmitted mostly among MSM is tone-deaf in itself. Like I wrote at the end of my comment, I think this information is important. I think it is the way in which you communicated that made it come across as tone-deaf.

(2) the definition of an STI is:

infections that are passed from one person to another through sexual contact. The contact is usually vaginal, oral, or anal sex. But sometimes they can spread through other intimate physical contact. This is because some STDs, like herpes and HPV, are spread by skin-to-skin contact. [link]

Based on this definition monkeypox is just as much an STI as herpes and HIV. A short google search about it seems to communicate that it's not being called an STI right now since it can cause stigma and stigma can hurt response efforts. But regardless definition has nothing to do with it. You can include it on an STI panel even if it's not strictly an STI, if it is more effective to do that to curb its spread.

(3) I do maintain that paying people to abstain is not an effective intervention. Sex isn't exactly a rational pursuit, and it'd be impossible to reinforce that.  Also the CDC does encourage condom use and there is an early study purporting to find monkeypox in semen.

I'm a microbiologist but not an expert in STIs and to me if this is being passed among mostly MSM, reducing the types of skin-to-skin contact that MSM have more often than others, should reduce the spread. Even if it won't bring cases down to 0.

Current reporting on monkeypox, particularly from government agencies/public health officials have been pretty terrible, trying to downplay that MPXV is predominantly spreading through sexual activity between men.

The only source for this claim you give is US based. I have not investigated this broadly, but the first two countries whose disease protection agencies I checked do make very clear that this outbreak is primarily in men who have sex with men.

The UK Health Security Agency on latest updates on monkeypox:

"While anyone can get monkeypox, the majority of monkeypox cases in the UK continue to be in gay, bisexual and other men who have sex with men, with the infection being passed on mainly through close contact in interconnected sexual networks."

The NHS Webpage on monkeypox says the same thing:

Anyone can get monkeypox. Though currently most cases have been in men who are gay, bisexual or have sex with other men, so it's particularly important to be aware of the symptoms if you're in these groups.

The German Robert Koch Institut (a federal government agency and research institute on disease control and prevention) on the monkeypox outbreak and cases and situation in Germany:

Die Übertragungen erfolgen in diesem Ausbruch nach derzeitigen Erkenntnissen in erster Linie im Rahmen von sexuellen Aktivitäten, aktuell insbesondere bei Männern, die sexuelle Kontakte mit anderen Männern haben.

(translated: According to most recent findings the infections in this outbreak are primarily occurring after sexual contact, especially in men who have sexual contact with other men. )

Fair, at the time, in late July, the NHS didn't have anything on MSM. The WHO and CDC continue not to. Those were the sources I checked.

I can't remember if we discussed this in our call, but one thing that's very plausible to me as an effective strategy is to include monkeypox in the suite of STI tests, at places like Planned Parenthood (I emailed Planned Parenthood but (reasonably enough!) they didn't get back to me). Also providing free and accessible testing at sex parties, and possibly recommend gating on them.

Note there is a suite of Metaculus questions on the outbreak, including chance of escaping the MSM community. The question suite was developed as part of a project for the Lancet medical journal. Currently the median forecast is that 94% of cases at the end of 2022 will be among MSM, with 89% being the 25% lower bound among 24 forecasters.

[Edit: Also, FWIW, I am queer and didn't have a problem with the wording at first, however on rereading I do think the first few lines need reworking. The summary sentence (MP is not worth worrying about) does hold true for EAs, but the positioning of the next sentence (it is mostly in the gay community) implies that is why MP is not worth worrying about. That is not why though. If Covid were limited to the gay community at first (or even ever), it would still be worth working on and worrying about. Regardless of whether or not MP is in the gay community, I think your thesis is that it is not worth worrying about  EA's because the transmission is pretty difficult and the risks of acquiring the infection are not so great. Therefore the harm you expect from MP is not very large compared to other things EAs could "worry about."]

A reasonably affordable intervention I haven't heard yet is disseminating actionable information to at-risk people: 

1. Locality and Community-Based:
Step 1: Pick a high density area and find out where and how people can get a monkeypox vaccine in that area.
Step 2: Design well-formatted info and send to relevant people:
-Contact sex workers and inform them where they can get a free vaccine. (contact info is on escort directory websites) 
-Contact swinger, sex, and kink clubs and email them a poster they can print and hang, or a graphic they can post on their social medias, that advises where to get monkeypox vaccines in their area. Also advice on how to deal with sheets and such to minimize risk of spread during play
-Same for gay clubs and hangouts, but probably more subtle as people don't have sex there
Step 3: Repeat for other cities

2. Web-Based:
Use advertisments on relevant apps (like Grinder, FetLife, Tinder)

I think both of these could like, employ a couple people fulltime for a month or 3 but not longer. Very cheap interventions. If you advertise well (like, make taking action seem a perk, eg, "you can tell your partners that you are vaccinated", "you can add it to your profile as a tag or show a photo of your vaccine papers and people will be impressed (we swear lol)") it could have success

(I funded Marcus with my own money to look into this).

Some quick takes:

  • As we've also observed for mid-2020 covid, Rt for sufficiently concerning diseases trends toward 1 by default because of control systems.
    • it makes a lot of rational selfish sense for people to take precautions up to the point where marginal risk equals marginal cost of additionally mitigating risk.
    • This is a pretty shitty failure of coordination (it sucks that people are taking precautions to avoid getting sick when they'll wound up getting sick anyway) but it doesn't rationally make sense for any individual to deviate
  • I disagree with "If you are a sexually active gay man , it is likely wise to limit your number of sexual partners as you are at a large risk." as an important takeaway.
    • As mentioned in the above point, MSM folks are already rationally incorporating personal risk into account so additional advice to be conservative here isn't very useful.
    • I also think almost all of the current spread happens at a relatively small number of sex parties.
  • The only things we can do to curb realistic spread is by taking actions that are large enough to push Rt<<1 hard. 
    • One plausible method is pushing for monkeypox vaccines, I think current guesses are that it reduces additional spread by 85%, which I think is enough to cut Rt <<1 even after behavioral changes (since R0~=2?).
      • I think for gay men who a) have sex regularly with many people and b) I personally know well enough to offer unsolicited advice and regularly (so, like, 3 people) "try to get vaccinated" might be my main advice
      • To be clear this advice is not without significant costs, the smallpox vaccines do have nontrivial side effects.
    • If we had a more sane public health system, offering regular and free monkeypox testing, and recommending that sex parties require them (the way they currently require covid tests) would also be a mainline intervention.
  • I think there is still a plausible case that EAs should try hard to curb monkeypox in at least one area, for epistemic reasons and as a way to get legible wins. 
    • I really think monkeypox is "easy mode" as public health interventions go, much slower serial interval than covid, fairly identifiable contact tracing, a vaccine already out, etc.
    • However I'm not personally super excited about working on this and this type of thing requires a fair amount of effort to be mobilized
  • The main takeaway I've had in the last few years is that prevention and (very) early-stage response is the most important thing for any emerging epidemic that you care enough to stop, ideally you want to cut spread while it's still in the exponential growth stage (and every doubling time approximately doubles the cost of trying to stop growth then).

For what it's worth, your summary gave me exactly the information I wanted and I'm glad you wrote it the way you did.

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