So far there is no evidence to suggest that corona viruses in general, or SARS-CoV-2 in particular, are purely seasonal.
The classic common cold viruses are rampant from autumn to spring, but show up throughout the year. It may well be that seasonal peaks become apparent.
This virus is going to be ubiquitous. How people adjust in the long term will determine the future of our industry. If the best case is that the virus is seasonal, eventually people may lose their desire for trans-equator international travel. If on average nine or ten passengers per plane load end up dead you can guess what will happen.