I read "Recommendations for the Use of Live Attenuated Varicella Vaccine" by the Committee on Infectious Diseases, which appeared in the May 1995 issue of Pediatrics. The recommendations do not address the problem of children who have had very mild cases of varicella and whether or not they should be immunized with the varicella vaccine.
About 10 years ago I began to keep records of children who had had very mild cases of varicella (under 20 lesions).