How does monkeypox spread? Here's what scientists know so far

Can you catch monkeypox from a toilet seat, or by trying on clothes at a thrift store? Is the virus spreading through bodily fluids? Can you pass it to your pets? 

Search for "monkeypox" on social media, and those are the kinds of questions you'll find online.

Several months into an unprecedented outbreak of monkeypox, platforms like Instagram, Twitter and TikTok are rife with sensationalized posts about how this virus might transmit, stoking potential fears that people can catch it in their day-to-day lives, even as data overwhelmingly points to sexual contact between men as a primary driver of global transmission. 

One analysis of monkeypox-related posts on Twitter, which was published in June as a letter to the editor in the Journal of Infection in Developing Countries, found more than half the posts contained misinformation or unverifiable details.

"There is a big difference between what is possible, and what is likely, and what is actually happening," said Len Tooley, director of evaluation at the Community-Based Research Centre, a queer health policy organization, and one of the first people to catch monkeypox in Toronto.

"What we see actually happening is it is mostly gay and bi men who are getting monkeypox. Most of them are getting it sexually … so if you don't fit into one of those two categories, you probably don't have too much to worry about."

While there are still key unanswered questions about the exact ways this virus spreads between hosts, data shows the bulk of infections remain among men who have sex with men — making it crucial, scientists say, to prioritize limited vaccines and supports to gay, bisexual and transgender individuals who are the highest risk of catching what's often a painful, weekslong illness.

"We know that sexual transmission in men who have sex with men is an important mechanism of spread and is contributing significantly to the ongoing outbreak," said physician and researcher Dr. Boghuma Titanji, an assistant professor at Emory University in Atlanta. "That being said, it is not the only method of transmission."

So here's what global researchers know — and don't — about how this virus transmits.

Before this year's global outbreak, scientists typically thought the monkeypox virus, or MPXV, primarily reached humans through contact with infected animals, leading to household transmission and limited outbreaks in regions of West and Central Africa where this pathogen is endemic.

But Titanji said there were hints MPXV was spreading through sexual networks as well, with Nigerian scientists ringing alarms during a countrywide outbreak in 2017 that largely impacted sexually active young men, often causing genital lesions.

"So it is possible that monkeypox has also been spreading through sexual contact and has kind of flown under the radar, and found its way into very densely connected sexual networks that allowed it to be amplified," said Titanji. 

In Canada, the disease is mostly reported among men who have sex with men, and 99 per cent of infected individuals identify as male, with a median age of 36.

Among U.S. monkeypox cases with available data, 99 per cent also occurred in men, including 94 per cent who reported recent male-to-male sexual or close intimate contact.