D.C. Mun. Regs. tit. 22, r. 22-B143
For a student who has not received a primary immunization, two (2) doses shall be administered. The second dose shall be administered not earlier than twenty-eight (28) days and not later than eight (8) weeks after the first dose.
MMR doses administered before the age of seven (7) may satisfy § 143.1, unless given before twelve (12) months of age or at an interval of less than twenty-eight (28) days between doses.
If single antigen measles, mumps, and rubella vaccines were administered, two (2) doses of each vaccine shall be administered not less than twenty-eight (28) days apart. A dose of any one (1) of the single antigen vaccines and a dose of another of the single antigen vaccines shall not be administered less than twenty-eight (28) days apart, unless administered on the same day. A dose of MMR, Varicella, one of the single-antigen measles, mumps, and rubella vaccines, or any other live parenteral vaccine shall not be administered less than twenty-eight (28) days apart, unless administered on the same day.
D.C. Mun. Regs. tit. 22, r. 22-B143