D.C. Mun. Regs. tit. 22, r. 22-B150
A student born in 1957 or later who has not received primary immunization shall receive two (2) doses of MMR. The second dose shall be administered not sooner than twenty-eight (28) days and not later than two (2) months after the first dose.
MMR administered before the age of eighteen (18) may satisfy § 150.1, unless given before twelve (12) months of age or at less than twenty-eight (28) days between each dose.
If single antigen measles, mumps, and rubella vaccines are used, 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. MMR shall not be administered within twenty-eight (28) days after a dose of varicella or one of the single-antigen measles, mumps, or rubella vaccines, unless administered on the same day.
D.C. Mun. Regs. tit. 22, r. 22-B150