Hypodermic needles are important for clinical practice.
But they can be painful, induce hypersensitivity, bruising, bleeding, contamination risks. Liquid drugs and vaccines have complex and expensive chains of cold storage.
Existing microneedling technologies have advantages over hypodermic needles but also bear limitations. They are not practical and unfit for specific uses. Dissolving microneedle patches are barely fit for cosmetic but not for medical use.