You can't make that assumption. There could be many reasons why deaths are declining such as earlier intervention and better treatment protocols. Deaths are a trailing indicator anyway it is the "worst and final resolution" of an active infection case. There are millions of infected out there who remain unresolved.
AFAIK from BoBeaux's daily stat threads, only about 12-14% of the population has been completely vaccinated and roughly an equal number received 1 of the 2 shots. This would mean some 70% of the population has not yet been vaccinated at all and yet the numbers of cases and deaths is way down (more than one would expect given the rate of vaccination). I am sure other factors are at play in the daily case/death counts besides the vaccines.
Regarding the treatment: I've really been wondering about that. Is there more standardization now? Less intubation right away? Are the obese housed in seated positions, or lying on their sides? It does seem the medical care at first was utterly chaotic.
Will we ever know the answers?
“only about 12-14% of the population has been completely vaccinated” (14% even, as of today)
About two weeks after a first shot though, you get better than 50% protection against developing symptomatic illness, and even better protection against hospitalization or death.
Those most likely to die (elderly or with co-morbidities) have been prioritized - magnifying the vaccine effect on death rate, relative to the general population. For young adults, COVID is not very fatal.
Virtually all US Nursing Home residents (who accounted for over 40% of COVID deaths last year) are now fully vaccinated. We just passed 70% of those 65 or older with at least a first shot, on today’s report.
Although there is a lag time for the immunity to fully manifest after vaccination, and between new cases and deaths; Crushing the COVID death rate should be pretty well be baked into the cake by the end of April - and is already, to a significant degree.