There are no eugenic implications in regards to Trump attempting to buy the rights to a COVID-19 vaccine, instead, the situation is far too over analyzed. For starters, the eugenic ideology entails that President Trump, and in turn, the American people believe that they are superior to other nations, and are actively attempting to purge the world of international populations. However, that is not the case. Instead, Trump is simply looking to put the American people first, a sentiment that all citizens should hold their own leaders too. Thus, this does not translate into a vision of a 'master race.' 
It is just an example of a good world leader.