Without looking at the numbers at all I'm pretty sure that number can be ignored almost completely. It's all but guaranteed to be vastly underreported, but fortunately none of the common STDs are deadly. HIV and hepatitis are both rare in Western countries and syphilis can be cured with antibiotics.

And HIV can be treated effectively nowadays. It's certainly not a death-sentence.

What you quoted does not really imply you are at an extreme risk of getting a deadly virus.

At 17%, if you do it a long period of time you definitely get it. Even if it isn't deadly virus, you get something nasty and most likely permanently.

9% of the workers reported never using a condom and a further percentage only use them sometimes. I suspect those are the majority of the 17% with an std.

Actually none of the zero-condom users reported getting a STD. My theory is that zero-condom users tend to be much more exclusive and to have fewer clients, or to do this closer to part-time?

I find it a bit surprising that 17% report STDs while only 9% report not using a condom at all. I would have expected causality.

Do you think condoms are always 100% effective at preventing all STDs?

No, but I'm surprised because 8 points of difference is a frigging lot.

"even if it isn't a deadly virus" is the relevant part here

For those with access to healthcare and regular checkups a typical STD is usually not deadly, including HIV.