Effective from Monday (13 December), fully vaccinated children can request an NHS letter proving their vaccination status for international travel purposes.
A person with legal responsibility for a child aged 12 to 15, such as a parent or guardian, can also request the document on their behalf.
Addressing the Commons on Monday, Javid said the move would allow "even more people" to prove their vaccine status for travel where it is needed.
The NHS Covid Pass is not available to children aged 12 to 15 who have received an incomplete course of vaccination, such as one dose of a two-dose vaccine.
Children under the age of 18 do not have to demonstrate their Covid status for entry to domestic events or venues in England.