D.C. Mun. Regs. tit. 22, r. 22-B134
The first dose of Haemophilus influenza type B (Hib) shall be administered no earlier than six (6) weeks of age and not later than two (2) months of age.
The second dose of Hib shall be administered no earlier than one (1) month after the first dose and not later than two (2) months after the first dose.
The third dose of Hib shall be administered no earlier than one (1) month after the second dose and not later than two (2) months after the second dose. The third dose shall not be required, if the PRP-OMP (PedvaxHIB) vaccine was administered for the first and second doses.
If different brands of licensed Hib conjugate vaccines are administered for the first two (2) doses, a total of three (3) doses shall be required to complete the primary series. Any combination of licensed Hib conjugate vaccines for use in infants may be administered to complete the primary series.
A booster dose of Hib shall be administered no earlier than two (2) months after the previous dose and at twelve (12) months of age and by sixteen (16) months of age.
An unvaccinated infant between the ages of seven (7) and eleven (11) months shall receive two (2) doses of Hib to complete the primary series, administered no earlier than one (1) month apart but not later than two (2) months apart. A booster dose shall be administered no earlier than two (2) months after the previous dose at twelve (12) months of age and by sixteen (16) months of age.
An undervaccinated infant between the ages of seven (7) and eleven (11) months shall complete the series according to the requirements of §§ 134.2, 134.3, and 134.5.
An unvaccinated or undervaccinated infant between twelve (12) and fourteen (14) months of age shall receive one (1) dose of Hib, followed by a booster dose. The booster dose shall be administered two (2) months after the previous dose.
An unvaccinated student between fifteen (15) months and five (5) years of age shall receive a single dose of Hib. A booster dose shall not be required.
The Hib vaccine shall not be required for a student five (5) years of age or older regardless of Hib vaccination status.
D.C. Mun. Regs. tit. 22, r. 22-B134