There have been many reports on this site over the years about JWs who accept blood transfusions, or transfusions of the "components" that JWs also prohibit for their adherents, after confirming with the medical staff that their decision will remain private from prying elders. I can't independently confirm those reports, but they certainly sound plausible.
I suspect it is quite common, and was so even before the current pandemic.
Heard that some jws died due to covid
There was a meeting on Friday between Bethel and COs, then COs passed the info to COBEs, and COBEs to elders, and then elders to publishers....the count of JWs who have died of COVID-19 in the US, as of Friday 4/17, is 250. I don't know the count for the entire world.