What is the minimum amount of time before second dose of varicella vaccine?

3 mos. The current expert opinion is a minimum of 3 months between the 2 doses.
Depends. The recommended interval between dose 1 and 2 is 3 months in kids under 4. The CDC accepts as valid, any dose given at least 4 weeks after the first in kids over a year as completing the 2 dose schedule.