First of all, Covid exists because some idiotic chingchongs decided it would be cool to eat inedible stuff. That has nothing to do with anyone else's political regime than the PRC; and arguably not even the PRC, directly.
...engaged in a trade war with the PRC, diminishing exchanges with it. So fewer Chinese people and goods were entering the USA even before the epidemic.
...set up a ban on visas for certain Middle Eastern countries, among them Iran, the main Middle Eastern hub of Covid. So fewer Iranian people were entering the USA even before the epidemic.
...brought back the economic sanctions against Iran. So fewer Iranian goods were entering the USA even before the epidemic.
...generally advocates for fewer immigrants and closed borders, which limits the number of people entering the USA, regardless of origin and regardless of temporary reasons like an epidemic. So fewer infected people from anywhere would be entering the USA.
Hillary's open borders policy would have brought Covid to the USA earlier and more widely. In specific cases, her reluctance to confront Iran and China would have helped the dispersal of the virus into American soil.
Btw, more Americans have died in Hillary endorsed wars from Somalia, through Yugoslavia and Libya to Iraq and Afghanistan, than have died of Covid. And this is unlikely to change even if infections keep on the rise.
And of course, being ultra cynic, Covid kills older people. Hillary endorses killing babies. (Another number Covid will never reach.)