A safety needle accessory includes a hub (6) having a connector (2) for surrounding a hollow needle. The hub has a first seal (10) that engages sealingly with the connector. A slidable sleeve (8) slides 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 to a third position in the second direction in which the needle is fully covered by the sleeve. A pack (9) having a closed end surrounds the hollow needle, hub and slidable sleeve. The pack has a first section which abuts the hub or the first seal to form a second seal and the pack has a second section which engages the needle tip to form a third seal (12) between the closed end of the pack and a needle tip.