My daughter was also diagnosed with this after a UTI at 6 months old. We did put her on daily antibiotics to prevent another infection and possible long-term effects. She was closely monitored and anytime she had an unexplained fever with no cold-like symptoms, we tested her urine to see if she had had a breakthrough infection. Luckily we never had a breakthrough infection.
Our pediatrician diagnosed her as Stage 5 on just the right side. We went to a specialist at Stanford (Lucille Packard Children's), who after reading the test results downgraded that to a Stage 4.
We repeated the tests (VCUG, ultrasound) approx 12 months after the initial tests. My husband and I were both shocked when the urologist told us that it had corrected itself - this was just before her 2nd birthday. We were fully prepared to have to entertain the option of surgery to correct it.
We were also told by the urologist to delay potty training slightly as the action of "holding" it could bring on the reflux again. However, she is now almost 4 years old, potty trained and we have not had another infection since the original one at 6 months old.
I hope that helps, but please let me know if you have any other questions.