It can be both! R does not tell you how many have got it/have had it - it simply tells you how many are infected by the average person with infection.
Most have not had it because most have not yet been exposed to it; when exposed, most get it. Of those, all are asymptomatic to start with, yet can spread it; some never develop significant symptoms, a % never develop any symptoms. Of course some unlucky ones end up in hospital, some very unlucky ones die.
Mike this is rubbish.
R = 4
It doesn't tell you how many have got it, but it tells you how many will get it.
If R was 4 pre lockdown, then 10-20 million would have had it before lockdown.
Or R wasn't 4.
Richard Taylor
"William Tell could take an apple off your head. Taylor could take out a processed pea."
Sid Waddell