Yes, but they're workers. People generally retire at 65, and in the MTA, I believe you can get a full pension at 55. The population that pushes up the mortality numbers are 70+, and they're not driving a bus or a train anymore.

Age is relevant here. I don't recall the numbers, but I read that a disproportionate amount of younger people who have died from covid-19 or had sever cases, were healthcare workers. And the theory was that viral load plays a part.

The Chinese doctor who blew the whistle on covid-19 died from it, and I believe he was an otherwise healthy 30-something.

Another explanation is high long-term stress related to handling the pandemic in hospitals, as stress has negative effect on immune system.

I suspect this would be facted on operators (trains, bus, etc.) versus support/construction/maintenance staff.