The vaccines don't prevent infection?

I have many concerns about the new mRNA vaccines for COVID-19, but I will save those for another post.  In this segment, I'd like to do a brief thought experiment.  The Pfizer and Moderna trials did not test whether their vaccines prevent people from getting infected by the virus.  Let me repeat that:  The Pfizer and Moderna trials did not test whether their vaccines prevent people from getting infected by the virus.  Their focus was on whether people in the study got symptoms.

This means that people who get vaccinated could still catch COVID-19, but the odds of them getting sick are much smaller (if the predicted efficacy rate is correct).  This also means that these people could still possibly spread the virus.  I foresee this potentially becoming a big problem.  Supposedly, asymptomatic spread is already an issue, but soon it may become a much greater concern. 

Most of the people who get the vaccines will think they are immune, but if they are not, they could unknowingly become super spreaders.  They will not stay home if they are sick because thanks to the vaccine, they won't have symptoms.  They will likely become lax with their personal hygiene and extra precautions.  In effect, they'll let their guard down.  I think this will make life even more risky for those who choose not to get vaccinated.

On the other hand, recent studies have shown that viral spread from asymptomatic people is extremely unlikely.  If this is true, it'd be huge because all this time, the "experts" were saying the opposite.

https://www.sacurrent.com/the-daily/archives/2020/12/12/here-are-answers-to-6-burning-questions-about-covid-19-vaccines