Try and add up known cases of children dying. I have been looking and I don’t actually see any support for the often quoted 0.2% fatality risk. In China people under 20 made 2.1% of known Coronavirus cases, but they represent a vastly larger share of the population. Italy and South Korea show mortality by age but zero deaths under 30.
I would now say that as “essentially immune,” but it does support them being at 1/100th the risk of 80+ year olds.
Further it also means shutting down schools early is extremely important. A largely asymptotic population in close contact with each other for hours a day is a nightmare for disease transmission.
So, no, they are not identical.
And from context you can also tell he's talking about otherwise healthy kids -- the "essentially" part of the actual quote.
It was a tweet...you all can read that far at least.
Edit: also, the headline (both here and on bbc.com) have "child immunity" in quotes, which are two words he did not say. He said, "Kids are essentially immune, but elderly with existing conditions are vulnerable." Yes, you could twist it around and say it was on the topic of 'child immunity', but it was put in quotes directly next to his name and was designed to inflame.