[R] survival::survfit.coxph confidence vs prediction intervals

[Gad Abraham]

Dear list,

I'm trying to understand what kind of uncertainty intervals are
plotted for survival::survfit.coxph when 'conf.int=TRUE' is called,
e.g.:

f <- coxph(Surv(futime, fustat) ~ age, data = ovarian)
s <- survfit(f, newdata=data.frame(age=c(30, 60)))
plot(s, conf.int=TRUE)

Are these bands the confidence intervals for the survivor function or
prediction intervals? Is it possible to get prediction intervals?

Regards,
Gad