A little bit, depending on the circuit.
The simplest way to model leakage in a BJT is as a resistor between collector & base. Not 100% accurate, but close enough. There are two ways that leakage is expressed: Iceo & Ices. Iceo is the current flowing from collector to emitter when the base is open circuit (the "o" in Iceo indicates the base is open). Ices is the current flowing from collector to emitter when the base is shorted to the emitter (the "s" in Ices indicates the base is shorted). These are both extreme conditions. What we see in a real circuit is something in between. Ices is the same as Icb since b is shorted to e. Let's think about the relationship between Iceo, Ices & HFE. In the Iceo measurement, the current that leaks from collector to base (which is the same thing as Ices), flows into the base, gets multiplied by HFE and creates Iceo.
In other words, Iceo = HFE x Ices.
Remember at the beginning of this discussion that I said we can approximate leakage as a resistor from c to b? If we know Vce (voltage from collector to emitter) when Ices is measured, then we can calc that resistor value, which we'll call Rlkg. Rlkg = Vce / Ices. I don't know what voltage the DCA75 applies to measure Ices, but I do know that my CCTT uses 5V to make measurements. So we'll assume that Vce = 5V. If HFE = 200 and Iceo = 1,000μA, then Ices = 1,000μA / 200 = 5μA. Now we can calc Rlkg. Rlkg = Vce / Ices = 5V / 5μA = 1MΩ. That's a pretty large resistance and will not do much to alter the performance of a Fuchsia or a Fuzz Face because the circuit impedance looking out from the transistor's base is 25K or less in the case of the Fuzz Face and around 15K in the Fuchsia.
There's actually more going on in the large-signal case where the transistor is being driven to cutoff and saturation, but this brief analysis gives the flavor of what to expect when using a leaky high-gain transistor.
