Patches set to take pain out of vaccination

Inoculating with needles and syringes is often prohibitively expensive because of the costs of trained medical staff. Photo / Bay of Plenty Times

A revolutionary way of vaccinating against infectious diseases has been invented by scientists who have developed a skin patch containing an influenza vaccine.

The patch does away with needles and syringes and could transform the battle against future pandemics by painlessly inoculating patients with vaccines that could be sent out in the post and self-administered in the home by somebody with no medical experience.

In the developing world, the skin patches could eliminate the need for the costly medical infrastructure of mass-vaccination campaigns, which require trained medical personnel to inject vaccines, and expensive storage equipment. Skin patches also bypass the hazards of dirty needles.

The skin patch is "armed" with an array of microscopic needles made of biodegradable plastic that painlessly scratch the surface of the skin and dissolve harmlessly without trace after delivering the vaccine safely inside the body.

Tests have shown that the patch works just as well and possibly even better than conventional vaccines injected into the body with needles and syringes. The skin patches are biodegradable and, unlike dirty needles, there is no risk of accidental skin pricks and cross-contamination.

Experiments on laboratory mice showed that the skin patches are even better than injectable vaccines at preventing flu infections because the vaccine enters the body via the surface of the skin, which is an important site of the immune system.

Most flu jabs, by comparison, deliver the vaccine into the muscles, which may not be the best place for triggering the all-important initial immune reaction.

Experts believe that if immunisations against flu and other infectious diseases could be delivered by skin patches, it would vastly improve the availability of vaccines in the developing world, where inoculating with needles and syringes is often prohibitively expensive because of the costs of trained medical staff.

In addition, skin patches do not need to be stored in refrigerators and they would solve the problem of re-using dirty needles and their safe disposal.

Professor Mark Prausnitz of the Georgia Institute of Technology in Atlanta, who led the research team, said the microneedle skin patch has the potential to revolutionise the way vaccines are delivered and administered because it is so simple and safe.

"In this study, we have shown that a dissolving microneedle patch can vaccinate against influenza at least as well, and probably better than, a traditional hypodermic needle."

More trials in animals will need to take place before the skin patches can be tried on human volunteers. It may still take many more years of clinical trials before vaccination by skin patch becomes routine.

How the patch works

* Each skin patch is armed with about 100 micro-needles that have been covered with molecules of the freeze-dried vaccine. When the needles penetrate the skin, they dissolve away within a few minutes, delivering the vaccine to the important cells of the body's immune system, which are always present in the skin.

* Scientists believe that when mass-produced, the skin patches could work out to be no more expensive than conventional vaccines delivered by needles and syringes. However, the overall costs of a vaccination programme should be lower because skin patches would not require expensively trained medical personnel, or the costs of disposing of hazardous waste in the form of dirty needles.

- INDEPENDENT