If the outbreak simply never makes it out of Wuhan, it's a non-issue in American politics by spring. If there is some gradual international spread and a series of foreign outbreaks stay in the news for several months, it could have an impact. Assuming Trump still institutes the China travel ban early and there is never a serious outbreak on US soil, it would help Trump in a "he kept us out of the war" kind of way.
Those things sound reasonable in such a universe. It might even be just forgotten for the most part.
