Vaccines can be delivered through the skin using ultrasound. This method doesn’t damage the skin and eliminates the need for painful needles. To create a needle-free vaccine, Darcy Dunn-Lawless at the University of Oxford and his colleagues mixed vaccine molecules with tiny, cup-shaped proteins. They then applied liquid mixture to the skin of mice and exposed it to ultrasound – like that used for sonograms – for about a minute and a half.
Hyposprays already were invented, mass produced, used as standard in the military for several years, and abandoned because they weren’t as hygienic as needles.
Anything that pushes through the skin into the blood pushes pathogens in too. Statistically, needles were safer so hyposprays were abandoned.
Presumably the version they use in Star Trek avoids that problem somehow, so it’s still a thing that would need to be invented.
The doctors are constantly jabbing people one right after another and often through the uniform…I’d love to see the explanation in universe for that
Medicine is improved so everyone has super immunity in the future. So it’s not that the hypo isn’t pushing dirt into their veins, it’s that they don’t care.
Maybe their uniforms are self-sterilizing.