Ah, thanks. It sounds like the logic of short term disability insurance from Social Security works similarly in both countries. The main difference appears to be that in the US the onus is on the worker to expressly make the claim and do the paperwork to receive payment from disability insurance, while in Spain the process is transparent for the worker, who superficially continues to receive payment from their employer even though the funds are ultimately coming from SS.
>>Mordis+(OP)
SSDI is not a short term, short term disability is a private insurance, usually provided as a benefit, but also available for purchase yourself.