Not much, if we're talking Marxist doctrines. The average Westerner associated communism with an authoritarian regime of government, rather than the lofty social ideals that Marx and Engels wrote about. This was because they only had the bloody revolution that had taken place in Russia to go on — but it can be argued that what the Bolsheviks did wasn't in line with Marx's ideology either, despite adopting the banner of 'communism'. Average citizens receive the education their state supplies them with, and if the Bolsheviks were claiming that everything they did was accurate in the eyes of Marx, international observers who'd never sat down to read his collective works had no reason to argue with the semantics.

As you ask about the West, I assume you're interested in what happened outside America. Two years after the Bolsheviks had seized power in 1917 Russia, Germany's home-grown Marxists were murdered during a general strike to prevent communism from taking over a freshly democratic state that had been weakened by the loss of its Kaiser. If we define the first Red Scare as taking place circa 1919, this powerful loathing of communists was developing concurrently to cartoons such as this being released in the USA. As this cartoon demonstrates by mislabelling its 'communist' caricature an 'anarchist', it was not necessarily Marx these people feared, but what people were doing in his name.

Even established democratic governments in Europe were terrified of a worker's revolution. It wasn't just the USA that feared this aspect of communist revolution the most. British newspaper The Daily Express commissioned newly-banished Bolshevik Trotsky to write articles about the horrors of Soviet Russia, under sensationalist headlines such as "Dramatic Revelations by Banished Revolutionary; The Use of Force Over a Rebellious People". For Trotsky, this was a chance to publicly slander the man who had unfairly kicked him out of Russia. For the British public, this was apparently confirmation from the horse's mouth that communism was a tyrannical form of government the world had never seen before.

It can be generally concluded that, by 1945, communism had grown so distant from Marx in public perception that your average citizen had no reason to care about the ideology it was meant to represent. What communism had objectively become was a callous system of government in which millions of people had been used as cannon fodder for a war effort. Reports of horror stories such as forced famines (in this case the Holodomor Genocide) resulting from the communist regime had been public knowledge since before the war, and it no longer mattered what a dead philosopher had intended people to take away from reading Das Kapital.