Dr Doctor (Doctor) Hoang Hirschberg, employed at RIVM, has carried out PhD research into three alternatives for needle injections. She concluded that all alternatives have advantages and limitations. Not one single delivery method will be generally applicable but depending on vaccine antigen, target population and market. Thanks to the numerous new technologies and extensive knowledge in this field Hirschberg is expecting that, in the future, more alternatives for needle injections will become available.
The administration of vaccines via bioneedles seems promising. Bioneedles are small, hollow implants, made from starch, which can be filled with vaccine antigens. After being shot under the skin using air pressure, the bioneedle dissolves allowing the vaccine to be released. Research with two vaccine antigens demonstrated that there is no need to store bioneedles in a cold location and that vaccination using this method induces the same antibody response in mice as regular vaccination through needle injection. In addition, in some cases this method requires less antigen. Bioneedles without antigen have been tested in humans and found to be safe. The main disadvantage is the small volume and lyophilising the vaccine is a difficult and expensive procedure.
Liquid jet injectors
Hirschberg also studied the liquid jet injector. The advantage of this alternative is that it uses the same liquid as a hypodermic needle, as a result of which less extensive research is required into the composition of the vaccine. With this method the vaccine is delivered into or through the skin under high pressure without the use of a needle.
This method, in which the skin is pre-treated with microneedles after which the vaccine is applied using a patch, results in a decreased production of antibodies in mice, compared to regular vaccination. The main advantage of this delivery method is that it is painless.
Hirschberg carried out her PhD research, independently of RIVM, at the former NVI (Netherlands Vaccin Institute) and in collaboration with Leiden University.