By Dr Jennifer Sisson*
Do you have a fear of needles? You’re not alone.
A Canadian study found 24% of adults and 63% children surveyed disliked having medical injections due to their fear of needles.
So, it’s hardly surprising that most people find the prospect of getting several vaccinations for an overseas trip daunting – even when they are recommended or actually required for entry or to return home.
But, there is good news for aichmophobics (people who fear sharp objects): A new generation of needle-free vaccines is in the wings.
Vaccination prevents millions of deaths
The world’s first vaccine, developed by English doctor Edward Jenner, was needle free. It prevented smallpox and involved arm-to-arm inoculation with the vaccinia virus.
Two hundred years later, illness-preventing vaccines involve one injection or a course of injections into the muscle or just under the skin of the arm, providing varying durations of protection (in some cases life-long).
‘Routine’ or childhood immunisations against measles, mumps, rubella, varicella, diphtheria, tetanus, whooping cough, Hepatitis B and polio continue to have a major global impact on infant mortality and public health. They’ve saved literally millions of young lives.
Those that protect travellers’ health may include such vaccines as hepatitis A and hep B, influenza, typhoid, cholera, meningococcal meningitis, Japanese encephalitis, and rabies – the make-up of the list very much depending on the who, what, where, when and how long of each individual trip and the medical history of the person travelling.
How vaccines prevent illness
Immunisation works on the principle that exposing the person (or animal) to a small part of a germ, or an artificial component resembling part of the germ, generates a protective immune response.
The body’s response to infection is generated in part by the skin and underlying tissue, which are rich with immune cells. That’s why most vaccines are delivered into the muscle or skin tissues via a needle.
One strategy to reduce the number of needles has been to combine several vaccines into one injection.
Despite this, Australian infants and toddlers still require up to 12 injections over 4 years to complete the recommended schedule – one reason a small percentage of parents refuse immunisation or defer scheduled vaccines.
Oral vaccines do exist, including polio (no longer used in Australia), typhoid, rotavirus and cholera. But, oral delivery can only be used for vaccines that can be administered directly to the gastrointestinal system, where they induce local immunity in the lining of the gut and stimulate the immune system to fight the offending bacteria and viruses.
Race on to develop pain-free products
Needle-free immunisation is an emerging technology that offers a painless 21st century solution to ensure the required ‘herd immunity’ of the population remains at high levels.
There are a number of delivery methods in development or undergoing testing for safety and effectiveness, including:
Nanopatch – The nanopatch is an award-winning Australian invention developed by Dr Mark Kendall at the University of Queensland. A small square of silicone with 20,000 vaccine-coated micro projections is placed on the surface of the skin to deliver the vaccine painlessly. It’s currently being tested to gauge how well it works with different vaccines.
Nasal spray – This technology is being used in much of the world (but not Australia) to deliver the seasonal flu vaccine. More recently, an inhalable Ebola vaccine has been trialled on primates.
Dry powder – Inhaled into the lungs, dry powder vaccines also show promise. They fight infections in much the same way as injectable vaccinations, but with fewer side-effects.
Pharmajet – More Australian technology, this device delivers the vaccine through the skin to the subcutaneous tissues or into the muscle under high pressure. Pharmajet injectors are being used in the United States, but not yet in Australia.
Sugar microneedles – Like the nanopatch, sugar discs feature multiple microneedles containing dried live virus vaccine to deliver the vaccine into the skin without a needle. Results to date are promising.
Edible vaccines – Edible vaccines are being developed, where the vaccine is delivered on an edible platform, such as a bacteria or plant.
Unshackling vaccines from cold chain
Besides the pain-free factor, some needle-free options don’t need to be delivered in a ‘cold chain’, a major advantage when it comes to vaccinating communities in remote regions of developing countries.
Needleless devices will also eliminate at least some of the risk of needle-stick injuries to health-care workers.
But, to ensure the community and the individual get maximum benefit from needle-free methods, many factors need to be weighed up – their cost, production capacity, storage conditions, and side effects.
Finally, needle-free vaccines need to be as good as or better at preventing disease than their injectable predecessors.
However, there’s no doubt that as new vaccines are developed, needle-free technology will become increasingly attractive – especially to anxious parents and needle-phobic travellers.
* Dr Sisson is the acting Medical Director of Travelvax Australia.
For more advice on vaccinations that may be recommended or required for your journey, call Travelvax Australia’s obligation free travel health advisory service on 1300 360 164 (toll-free from landlines). You can also make an appointment for a pre-travel medical consultation at a Travelvax clinic to receive vaccines, any medication required, accessories, and personalised advice tailored to your itinerary and your medical history.