That's a complete lie. Trump failed miserably in preventing sick people from getting into the country or spreading covid because he refused the WHO tests for covid, wanting a "made in America" test so that Big Pharma could have the "rights" and profits to such technology.
The CDC, under Trump's hand picked loyalist (very unqualified), botched the covid test rollout, and ultimately gave up trying. Big Pharma just put out whatever they felt would sell, and testing in the USA never became reliable or quick.
Trump failed to provide a testing system for people entering the USA, and admitted thousands of people returning from China without testing them on entry. Subsequent DNA testing proved that the virus mostly came in from Europe, primarily Italy which was the first western nation hit.
In any case, Trump failed utterly to keep the virus out of the USA, or to prevent it from spreading once it got there. The largest number of cases, and the highest numbers of deaths in the first world.