D.C. Mun. Regs. tit. 22-B, § 138
138.1 Beginning with the 2009/2010 school year, two (2) doses of hepatitis A vaccine shall be administered to each student born on or after January 1, 2005.
138.2 The first dose of hepatitis A shall be administered no earlier than twelve (12) months of age and by twenty-four (24) months of age.
138.3 The second dose of hepatitis A shall be administered not earlier than six (6) months and not later than twelve (12) months after the first dose and by thirty-five (35) months of age.
138.4 An unvaccinated or undervaccinated student more than twenty-four (24) months of age and less than age seven (7) shall receive two (2) doses of hepatitis A vaccine administered not less than six (6) months apart and not later than twelve (12) months after the first dose.
SOURCE: Final Rulemaking published at 55 DCR 5253 (May 2, 2008).