This invention relates to a safety needle accessory sealed within a pack suitable for sealing pre-filled syringes. The safety needle accessory comprises a hub for surrounding a hollow needle having a tip and having a connector for attachment to a syringe, a slidable sleeve adapted to slide over the needle in a first longitudinal direction from a first position in which the needle is fully or partially covered by the sleeve to a second position in which the needle is exposed, and in a second longitudinal direction from the second position to a third position in which the needle is fully covered by the sleeve, and a pack surrounding the hollow needle, hub and slidable sleeve having a closed end covering the needle and an open end exposing the connector of the hub. The safety needle accessory further comprises a first seal attached to the connector of the hub and a second seal between the hub and the pack.