Non-sterilizing vaccines still reduce viral load, decreasing the amount of active viral particles in circulation. There are plenty of vaccines we use to curb epidemics that aren't full sterilizing vaccines.

For the COVID-19 U.S. vaccines in particular:

> Preliminary data from the clinical trials among adults ≥18 years old suggest COVID-19 vaccination may also protect against asymptomatic infection.[0]

[0] https://www.cdc.gov/coronavirus/2019-ncov/science/science-br...

The vaccines do reduce the chances of transmission quite significantly, so it makes sense to get vaccinated if your goal is to protect others. It doesn't need to be 100 percent sterilizing to be helpful in this regard.