Dissolvable flu vax patch preferable to injections

Dissolvable vaccine patch could result in less sharps waste, doesn’t require refrigeration and may be self-applied.

A safe and alternative method of delivering the influenza vaccine has been found to be both safe and preferred to conventional injections.

Delivering the influenza vaccine via a dissolvable microneedle patch was safe and preferred, according to a new phase 1 trial involving 100 people, published in The Lancet.

The study is the first randomised trial to test a self-administered, dissolvable microneedle patch vaccine in humans, and found that the microneedle patch could be safely self-administered by participants, and was stable for one year at 40°C, potentially reducing delivery and storage costs. Analysis of the patches also found that the microneedles successfully dissolved, thereby eliminating safety risks associated with used hypodermic needles.

The study, led by Emory University and Georgia Institute of Technology, USA, further indicated that the microneedle patch leads to a robust immune response similar to conventional intramuscular injection, but larger trials are needed to further investigate the immune mechanism behind the response and confirm the findings.

In the USA, even with the recommendation for universal vaccination, coverage of influenza vaccination remains below 50% and influenza continues to be a major cause of morbidity and mortality, resulting in up to 48,000 deaths per year. In the UK, the flu vaccine is offered to everyone aged 65 and over, pregnant women, health workers and children aged 6 months to 2 years. In Australia, it is estimated that each year influenza causes an average of 13,500 hospitalisations and more than 3000 deaths among Australians aged over 50 years.

Vaccination by microneedle patch could improve vaccination coverage because the patch could be stored and distributed without refrigeration and may be safely self-administered by patients without the need for trained health professionals.

The trial involved 100 people aged 18–49 who had chosen not to receive the available influenza vaccine for that season. Participants were randomly assigned to one of four groups: they received either a vaccine microneedle patch, vaccine injection or placebo microneedle patch administered by a health professional, or a self-applied vaccine microneedle patch. Participants received a single dose of inactivated influenza vaccine (fluvirin).

The vaccine injection was given in the arm and the microneedle patch was applied for 20 minutes on the wrist.

The microneedle vaccine patch, which contains tiny needles that dissolve into the skin, carrying vaccine.

Participants who self-applied the patch were given instructions via a brief audiovisual presentation. The study was primarily designed to assess safety and acceptability, but also investigated immunogenicity.

At 6 months, no serious side effects linked to the vaccine were reported and there were no cases of influenza in any of the groups. Minor reactions to the vaccine were mild and transient. Pain and tenderness were most commonly reported in the injection group, and redness, itching and tenderness in the vaccine microneedle patch groups.

Immediately after receiving the vaccine, participants reported high acceptability with scores of 4.5–4.8 (out of 5) in the three microneedle patch groups, similar to the injection group (4.4). At 28 days post-vaccination, 70% (33/47) of participants who had received the microneedle patch vaccine said they preferred it to the injection.

Dr Nadine Rouphael, Associate Professor of Medicine at Emory University, USA, and lead author of the study, said because the vaccine was stable outside refrigeration, “… it could potentially be stored on a pharmacy shelf. The patch could also be safely applied by participants themselves, meaning we could envisage vaccination at home, in the workplace or even via mail distribution. These advantages could reduce the cost of the flu vaccine and potentially increase coverage. Our findings now need confirming in larger trials.”

Top image credit: The microneedle vaccine patch being applied to a study participant. Some participants applied the patches to themselves. © Rob Felt/Georgia Tech.