Does bed resting actually speed up disease recovery or not?

[Bosh]

Title.

[apud.harald]

https://rimworldwiki.com/wiki/Bed

While resting in a bed, colonists heal by an additional 8 HP per day -- see injury for details. Beds can be walked over, although at a slower rate.

https://rimworldwiki.com/wiki/Disease

Immunity: Colonists will gradually develop immunity to potentially fatal diseases, such as wound infections or plague. When immunity reaches 100%, the symptoms will not immediately disappear, but will instead tick backwards towards zero with the colonist no longer needing any treatment. If the disease symptoms progress past 100% before immunity does, the colonist will die. Immunity Gain Speed is affected by the colonist's food, rest, bed quality, age, and blood filtration

Totally unrelated: looking it up taught me that stone beds are inefficient for rest.
I should stop making stone beds. Thank you for asking the question!

[Astasia]

Resting in a bed increases immunity gain speed by quite a bit.

[Burki from Turki]

yes you want to keep them in beds so they can both have a faster immunity gain (not really that much, around 3 to 8 percent forgot the exact number) and always be ready for next tending as they can sometimes miss tending doing time taking jobs which allows the disease to grow faster and bypass the immunity

[Astasia]

It's +8% for the bed, there's another +10% for the act of resting. It's pretty huge in practice because of the way diseases work. It's not always needed, especially later on with better tends and other immunity gain boosts, but early on if you keep your sick colonists in bed it means you don't really have to worry about bad tends killing them (unless you chain 0s).

[Morkonan]

I had four out of six colonists get the plague last night. They survived ONLY because of that small percentage advantage that bed rest gives. Two of them squeezed by the timer by a few ticks of the clock... If I hadn't immediately reacted and ordered Bed Rest, I'm not sure they would have made it. The one I was most concerned about was the one it took the longest to walk to my Infirmary.

[gimmethegepgun]

Also do remember that different diseases respond differently to treatment. A great tend on an infection will almost stop the progression of the disease, but the flu doesn't change a whole lot from tending. Diseases that don't respond much to tending are generally more important to have rest than the ones that really respond to it (and are also more dangerous for old people since you can't really lean on meds to save them)

[Professor H. Farnsworth]

Beds will tell you exactly how much they improve rest/immunity - it's the percentage usually in-between 100-112% (though it could be more, it's been a while)
Beds turned Medical are even better at immunity gain rates, but I forget how much their modifier for immunity gain is. They also reduce the chance of infections (cleanliness plays a much bigger role in this - keep your colony tidy).
Quality also affects the overall rest/immunity gain.