Question: Watching various COVID-related briefings, I notice there is always a sign language interpreter. This is clearly necessary, yet thinking about all the conferences I've attended in the past, literally none of them have had a sign language interpreter.

How do conferences work for deaf scientists? Do deaf scientists simply not attend conferences? If so, how does one even work in fields such as computer science where conferences are an integral part of the academic experience?

Answer: 
I am neither a deaf scientist nor an organizer for conferences. However, I was a student and staff member at a university with a significant deaf population so I'll speak from that perspective.

The prevalence of interpreters and other accommodations for those with disabilities varied significantly. It was a given that American Sign Language (ASL) interpreters would be present at large scale events and presentations aimed at the community as a whole. Additionally, interpreters would be provided for deaf students taking classes taught in spoken English.

Beyond that, it was usually the responsibility of the deaf person to arrange for an interpreter; though many interpreters were employed by the university, there was no guarantee one would be available on short notice. This may explain why I seldom saw interpreters at club meetings and other smaller events, especially those that emphasized spontaneous direct communication. For example, interpreters were present at the anime club where much of the activities involved watching Japanese animation with subtitles, but I did not see any at the club for tabletop role playing games where interpersonal interaction was constant.

In short, students and staff had the accommodations necessary to fulfill their primary goal(s) but often not enough for secondary ones, such as socialization. I suspect a similar dynamic applies to scientific conferences.

Conferences that regularly have deaf people attending likely organize interpreters themselves but the rest will only provide accommodations when requested. (In other words, at a typical conference, you're not going to see an ASL interpreter unless there's at least one deaf person present!) The effectiveness of such accommodations are apt to suffer if the organizers lack experience and/or resources. This would discourage deaf people from attending unless the conference was essential - for example, a topic of particular interest is being discussed or a colleague is in need of material or moral support - or had a positive reputation of proper accommodations.

In summary, the attendance of deaf scientists at conferences is presumably dictated by the following:

* The importance of the conference to the individual deaf scientist
* The presence and quality of accommodations that enable deaf scientists to be productive
* The number of people with whom the deaf persons can readily communicate with
* Each deaf scientist's personal comfort level with attending conferences designed primarily for hearing people
They do not work. Most conferences in most fields of science do not work well for people with any sensory/communication disabilities.

A few online conferences offer automatically generated captions. These help some but they are not very accurate.

Edit: The fact that conferences are ableist is not because they are intentionally ableist, but rather because of ignorance. Many conference organizers would be willing to adjust their conferences if they knew how to do so and had the funds.