Most vaccines are administrated by injection, which requires syringes, needles, and trained personnel. On top of this, it's no secret that injections can also be painful and cause stress (as highlighted in my mini-study on top 10 most commonly expressed public opinions on vaccination on Twitter). I decided to have a look at what other up-and-coming vaccine delivery methods were out there, and this is what I found.
1. Needle-free patch
A needle-free vaccine technique would involve a disc-shaped microneedle array, about the size of a contact lens. The microneedles – made of sugar – penetrate the skin and dissolve after about 5 minutes. Scientists at King's College have demonstrated the ability to deliver a dried live vaccine to the skin without a traditional needle, and shown for the first time that this technique is powerful enough to enable specialised immune cells in the skin to kick-start the immunising properties of the vaccine. Click here to see the video >
There are 5 main benefits of the technology over conventional injections:
- Dried live vaccine within the microneedles remains stable and effective at room temperature
- Overcoming issues concerning vaccine transportation
- Vaccine could be self-administered
- As the needle simply dissolves, the technology also overcomes the concerns over safe disposal
- Potential for more of the public to be open to vaccination- a potentially painless alternative to hypodermic needles
2. Inhaled vaccines
Of course, inhaled vaccines are already used in some cases. For instance, MedImmune's intranasal vaccine FluMist is a vaccine sprayed into the nose to protect against influenza (see Top 4 influenza vaccine FDA approvals) – doing away with needles and painful arms.
However, even more excitement lies in the development of pulmonary vaccine delivery – that is, vaccines delivered through the lungs. Such a method has gained increasing attention during the last decade because it would not only omit the use of needles but may also elicit immunity at the port of entry for many pathogens.
“The lung is an immunologic powerhouse that remains largely unexplored. Theoretically we should be able to avoid needles and simply inhale our vaccines,” said Gerald C. Smaldone, MD, PhD, Editor-in-Chief of Journal of Aerosol Medicine and Pulmonary Drug Delivery.
One disease for which inhalable vaccines are being tested is measles, which remains an important cause of childhood mortality worldwide. In 2011, a team of researchers at the Johns Hopkins Bloomberg School of Public Health and the University of Colorado developed and successfully tested a dry powder, live-attenuated inhalable measles vaccine in rhesus macaques. According to the study, the new dry powder measles vaccine provided the macaques complete protection from measles with a single vaccine dose. Read the study here >
“An effective dry powder vaccine would be tremendously helpful in less developed regions where resources are limited,” said Diane E. Griffin, MD, PhD, senior author of the study and chair of the W. Harry Feinstone Department of Molecular Microbiology and Immunology at the Bloomberg School of Public Health. “This vaccine can be shipped as powder and does not require reconstitution or special training to administer, which could greatly increase the ease and safety of measles vaccination worldwide.”
3. Oral vaccines
Oral vaccines already currently exist to protect against polio and cholera. However, oral vaccines are also under development to protect against tuberculosis. A study by researchers at Royal Holloway, University of London, in collaboration with the Universita Cattolica del Sacro in Rome and RecipharmCobra Biologics showed that the orally delivered vaccine produced higher immune responses than the injected DNA vaccine.
4. Microneedle arrays
The transcutaneous route is particularly attractive because the skin is highly accessible with unique immunological characteristics.
Microneedle arrays – that is, needles that are shorter than 1mm with a cross-sectional diameter of about 300 Âµm – could theoretically penetrate the stratum corneum in a painless manner. Such arrays could consist of solid microneedle arrays, coated microneedle arrays, hollow microneedle arrays and dissolvable microneedle arrays.
5. Disruption of the stratum corneum
Transcutaneous immunization (TCI) has become an attractive alternate route of immunization due to increased understanding of the skin immune system and to recent technical innovations in skin patch delivery systems.
Skin abrasion, with a device such as Intercell's (Iomai) tape-stripping skin preparation system, could partially remove the stratum corneum before application of a vaccine patch. Read more about transcutaneous immunization here >
Other interesting vaccine delivery methods also exist. For instance, researchers at the Seoul National University in South Korea developed a laser device that can apparently could replace traditional needles with a less painful jab. Read the BBC article > Other methods include the use of ultrasound, high-voltage electrical pulses to disrupt lipid structures, thermo-ablation and various chemical approaches to enhance penetration. Read more about these here >
What other up-and-coming vaccine delivery methods do you think are important? You can join our discussion on LinkedIn or leave a comment below, I'd love to hear what you think.