Drunkard’s Walk (1960), by Frederik Pohl.

Spoilers & speculation:

A mathematics teacher keeps trying to kill himself in this somewhat satirical novel set in 2166 A.D. Why? The big reveal comes in the final chapters, where we learn that telepathic immortals are behind his suicides, because he and his kind are too close to them genetically. They fear competition. Being found out. So fearful are they that they unleash a worldwide plague to kill off much of humanity.

October 1969 edition, p. 138.

So I wonder: when our civilization develops truly successful life-extension methods, the political ramifications will necessarily become enormous. To fend off demographics-based chaos, the new immortals will seek to severely cut down the size of the global population, probably with a series of plagues . . . and rigged inoculations.

How will we know when the big advances in longevity research had’ve been achieved? When we witness a series of designer diseases with designer drugs developed in tandem.

Has the crucial advance in longevity research been achieved? Yes: it has already happened. SARS-CoV-2.

The novel lacks something, though it is very well-written, the first half reading more like a satire of academic life than an sf novel. But one reads science fiction at least partially to make one think. A thumb’s up.