Short answer. Yes. RA 9048 contains a retroactivity clause, so it reaches clerical or typographical errors in a birth certificate that were made before the law took effect. The one condition is that applying it must not prejudice or impair vested or acquired rights under the Civil Code and other laws.
What the law says
This Act shall have retroactive effect insofar as it does not prejudice or impair vested or acquired rights in accordance with the Civil Code and other laws.
RA 9048, Section 11 — Retroactive But Not Prejudicial. Read the full provision →
The law looks backward
Many laws apply only to events after they take effect. RA 9048, which allows certain corrections of civil registry entries without going to court, is different because it carries an express retroactivity clause. It states: This Act shall have retroactive effect insofar as it does not prejudice or impair vested or acquired rights in accordance with the Civil Code and other laws. This means the age of the error is not, by itself, a bar. A clerical or typographical mistake entered in your birth record long before the law existed can still be brought under its correction procedure, provided the limit below is respected.
The condition: no prejudice to vested rights
Retroactivity here is not unlimited. The clause makes the reach of the law conditional: it applies backward insofar as it does not prejudice or impair vested or acquired rights. A vested or acquired right is one that has already become fixed and belongs to a person under existing law. If correcting an old entry would take away or damage such a right that someone else has legitimately acquired, the retroactive effect yields to that point. In the ordinary case of fixing a plain spelling slip or an obvious typographical error, no such right is usually disturbed.
What kinds of errors this covers
The retroactivity clause governs the reach in time, but the law's substance limits the kind of change allowed. RA 9048 is aimed at clerical or typographical errors — the sort of harmless mistakes clear on the face of the record — and at the change of a first name or nickname under its own conditions. It is not a route for altering matters that go to a person's status or filiation, which the law keeps outside this simpler administrative process. Being old does not turn a substantive change into a clerical one; the nature of the error, not its age, decides eligibility.
Why this matters to you
If your birth certificate has carried a typographical or clerical error since before the law took effect, this clause means you are not shut out merely because the mistake is that old. You may still avail yourself of the administrative correction it provides, subject to its requirements and to the vested-rights limit. The practical questions are whether your particular error is the clerical or typographical kind the law addresses, and whether correcting it would impair anyone's already-acquired rights. Where it would not, the age of the error is not the obstacle.