Not necessarily.
An exponentially growing respiratory system contagion with no adequate medical treatment can cross the tipping point from invisible to single greatest cause of mortality in a few days. How far - that measure - this virus is from its tipping point to plague is not known, and may change at any time (mutations being frequent in these kinds of infections, while selection pressure is nearly ideal for its rapid evolution in places like the US that 1) lack key features of modern public health setups 2) have a mobile population. (The snowbirds are packing for their northern migration from the coastal States and busy southern ports even now).
As far as thread relevance - a plague virus will surely and significantly interfere with the kinds of deliberate efforts a response to AGW would require. But it may reduce CO2 output, and slow AGW down - plagues in the past seem to have delayed or reduced the effects of agriculture and other aspects of civilization on climate worldwide, simply by destroying the agriculture and those other aspects. This one would have to kill more people to bring the same benefit, but that's not impossible.