Parvo virus aka slapcheek is highly contagious and is spread by droplet. This is why a large number of the adult population are immune because a large number have been in contact with it.

So, you sneeze an put your hand over your mouth and then shake my hand and I wipe my mouth and there is a good chance that communication has taken place.

Slapcheek is often a very mild illness in children with a runny nose but the red slapped affect the cheeks get is a give away.

Generally speaking youshould be screened / tested for CMV, Parvo, toxo, varicella, rubella on your routine bloods. Check with your doctor. If you haven't been tested it's worthwhile just so you know that you need to be a little more wary.
CMV, Parvo and toxo are not illnesses that you can be vaccinated for so the only immunity you will have is if you have been exposed.
I hope that helps