No source, but not seeing anybody saying death rate is going up in conjunction with infection. It's more infectious for sure. For Ontario where I live about 88% of the infected are from the Delta and deaths are almost at an all time low. Probably because most older people are not getting infected as much and it's mostly a younger demographic. For example in Ontario there's been about 10,000 deaths all but 750 of those are from the 60 and up age group with 90% in the 80 plus. 40 to 60 yrs old total deaths are about 650 people. Under 40 years old total deaths are about 100 and that's who's getting infected so it makes sense. The death rate for under 60 is 0.4% and under 20 yrs of age we've had 6 deaths.
Delta is definitely more infectious. It spreads very proficiently. It is also sending more younger people to the hospital than previous strains, including children. I don't know about death rates right off hand. I do know that hospitals, and hospital staff (like my sister) are being pushed to the limits in places like Florida and Texas.
Another thing I know, is that a lot of videos are coming out from anti-vaxxers on their death beds pleading with people to NOT make the same mistake they did, and go get vaccinated. I have know idea if it is having any effect. Like comedian Jeff Foxworthy says, "You can't fix stupid."
CD