You are much less likely to catch COVID-19, become seriously ill, or spread the virus when gathering with people who are up to date on their vaccinations. Masks add a layer of protection when worn indoors with people from outside your household or outdoors in large group settings. This is true whether you are in a public or private location.
If you are up to date with your COVID vaccinations and it turns out that you ARE exposed to COVID — and if you do not have symptoms — you don’t need to quarantine. Just in case, though, you should get tested 5 days after your last contact with the person with COVID, regardless of whether you have symptoms or not.
SOURCE: https://www.muhealth.org/our-stories/youre-vaccinated-against-covid-19-now-what (Michigan University)